]> www.ginac.de Git - ginac.git/blobdiff - ginac/expairseq.cpp
basic, expairseq: use standard C++ RTTI in compare(), is_equal(), match(), etc.
[ginac.git] / ginac / expairseq.cpp
index f9347e0b364961378a21421f6f8e40121770ea7c..120672f74498f3d44915ee77d71e91e48af6f1a6 100644 (file)
@@ -3,7 +3,7 @@
  *  Implementation of sequences of expression pairs. */
 
 /*
- *  GiNaC Copyright (C) 1999 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2008 Johannes Gutenberg University Mainz, Germany
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#include <iostream>
 #include <algorithm>
 #include <string>
 #include <stdexcept>
+#include <iterator>
 
 #include "expairseq.h"
 #include "lst.h"
+#include "add.h"
+#include "mul.h"
+#include "power.h"
+#include "relational.h"
+#include "wildcard.h"
+#include "archive.h"
+#include "operators.h"
+#include "utils.h"
+#include "indexed.h"
+
+#if EXPAIRSEQ_USE_HASHTAB
+#include <cmath>
+#endif // EXPAIRSEQ_USE_HASHTAB
+
+namespace GiNaC {
+
+       
+GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(expairseq, basic,
+  print_func<print_context>(&expairseq::do_print).
+  print_func<print_tree>(&expairseq::do_print_tree))
 
-#ifdef EXPAIRSEQ_USE_HASHTAB
-#error "!!!!!!!!TODO: expair_needs_further_processing not yet implemented for hashtabs, sorry. A.F."
-#endif // def EXPAIRSEQ_USE_HASHTAB
 
 //////////
 // helper classes
 class epp_is_less
 {
 public:
-    bool operator()(epp const & lh, epp const & rh) const
-    {
-        return (*lh).is_less(*rh);
-    }
+       bool operator()(const epp &lh, const epp &rh) const
+       {
+               return (*lh).is_less(*rh);
+       }
 };
 
 //////////
-// default constructor, destructor, copy constructor assignment operator and helpers
+// default constructor
 //////////
 
 // public
 
-expairseq::expairseq(expairseq const & other)
-{
-    debugmsg("expairseq copy constructor",LOGLEVEL_CONSTRUCT);
-    copy(other);
-}
-
-expairseq const & expairseq::operator=(expairseq const & other)
-{
-    debugmsg("expairseq operator=",LOGLEVEL_ASSIGNMENT);
-    if (this != &other) {
-        destroy(1);
-        copy(other);
-    }
-    return *this;
-}
+expairseq::expairseq() : inherited(&expairseq::tinfo_static)
+#if EXPAIRSEQ_USE_HASHTAB
+                                                   , hashtabsize(0)
+#endif // EXPAIRSEQ_USE_HASHTAB
+{}
 
 // protected
 
-void expairseq::copy(expairseq const & other)
-{
-    basic::copy(other);
-    seq=other.seq;
-    overall_coeff=other.overall_coeff;
-#ifdef EXPAIRSEQ_USE_HASHTAB
-    // copy hashtab
-    hashtabsize=other.hashtabsize;
-    if (hashtabsize!=0) {
-    hashmask=other.hashmask;
-        hashtab.resize(hashtabsize);
-        epvector::const_iterator osb=other.seq.begin();
-        for (unsigned i=0; i<hashtabsize; ++i) {
-            hashtab[i].clear();
-            for (epplist::const_iterator cit=other.hashtab[i].begin();
-                 cit!=other.hashtab[i].end(); ++cit) {
-                hashtab[i].push_back(seq.begin()+((*cit)-osb));
-            }
-        }
-    } else {
-        hashtab.clear();
-    }
-#endif // def EXPAIRSEQ_USE_HASHTAB
-}
+#if 0
+/** For use by copy ctor and assignment operator. */
+void expairseq::copy(const expairseq &other)
+{
+       seq = other.seq;
+       overall_coeff = other.overall_coeff;
+#if EXPAIRSEQ_USE_HASHTAB
+       // copy hashtab
+       hashtabsize = other.hashtabsize;
+       if (hashtabsize!=0) {
+               hashmask = other.hashmask;
+               hashtab.resize(hashtabsize);
+               epvector::const_iterator osb = other.seq.begin();
+               for (unsigned i=0; i<hashtabsize; ++i) {
+                       hashtab[i].clear();
+                       for (epplist::const_iterator cit=other.hashtab[i].begin();
+                            cit!=other.hashtab[i].end(); ++cit) {
+                               hashtab[i].push_back(seq.begin()+((*cit)-osb));
+                       }
+               }
+       } else {
+               hashtab.clear();
+       }
+#endif // EXPAIRSEQ_USE_HASHTAB
+}
+#endif
 
 //////////
 // other constructors
 //////////
 
-expairseq::expairseq(ex const & lh, ex const & rh) : basic(TINFO_expairseq)
+expairseq::expairseq(const ex &lh, const ex &rh) : inherited(&expairseq::tinfo_static)
 {
-    debugmsg("expairseq constructor from ex,ex",LOGLEVEL_CONSTRUCT);
-    construct_from_2_ex(lh,rh);
-    ASSERT(is_canonical());
+       construct_from_2_ex(lh,rh);
+       GINAC_ASSERT(is_canonical());
 }
 
-expairseq::expairseq(exvector const & v) : basic(TINFO_expairseq)
-{
-    debugmsg("expairseq constructor from exvector",LOGLEVEL_CONSTRUCT);
-    construct_from_exvector(v);
-    ASSERT(is_canonical());
-}
-
-/*
-expairseq::expairseq(epvector const & v, bool do_not_canonicalize) :
-    basic(TINFO_expairseq)
+expairseq::expairseq(const exvector &v) : inherited(&expairseq::tinfo_static)
 {
-    debugmsg("expairseq constructor from epvector",LOGLEVEL_CONSTRUCT);
-    if (do_not_canonicalize) {
-        seq=v;
-#ifdef EXPAIRSEQ_USE_HASHTAB
-        combine_same_terms(); // to build hashtab
-#endif // def EXPAIRSEQ_USE_HASHTAB
-    } else {
-        construct_from_epvector(v);
-    }
-    ASSERT(is_canonical());
+       construct_from_exvector(v);
+       GINAC_ASSERT(is_canonical());
 }
-*/
 
-expairseq::expairseq(epvector const & v, ex const & oc) :
-    basic(TINFO_expairseq), overall_coeff(oc)
+expairseq::expairseq(const epvector &v, const ex &oc, bool do_index_renaming)
+  : inherited(&expairseq::tinfo_static), overall_coeff(oc)
 {
-    debugmsg("expairseq constructor from epvector,ex",LOGLEVEL_CONSTRUCT);
-    construct_from_epvector(v);
-    ASSERT(is_canonical());
+       GINAC_ASSERT(is_a<numeric>(oc));
+       construct_from_epvector(v, do_index_renaming);
+       GINAC_ASSERT(is_canonical());
 }
 
-expairseq::expairseq(epvector * vp, ex const & oc) :
-    basic(TINFO_expairseq), overall_coeff(oc)
+expairseq::expairseq(std::auto_ptr<epvector> vp, const ex &oc, bool do_index_renaming)
+  : inherited(&expairseq::tinfo_static), overall_coeff(oc)
 {
-    debugmsg("expairseq constructor from epvector *,ex",LOGLEVEL_CONSTRUCT);
-    ASSERT(vp!=0);
-    construct_from_epvector(*vp);
-    delete vp;
-    ASSERT(is_canonical());
+       GINAC_ASSERT(vp.get()!=0);
+       GINAC_ASSERT(is_a<numeric>(oc));
+       construct_from_epvector(*vp, do_index_renaming);
+       GINAC_ASSERT(is_canonical());
 }
 
 //////////
-// functions overriding virtual functions from bases classes
+// archiving
 //////////
 
-// public
-
-basic * expairseq::duplicate() const
+expairseq::expairseq(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
+#if EXPAIRSEQ_USE_HASHTAB
+       , hashtabsize(0)
+#endif
 {
-    debugmsg("expairseq duplicate",LOGLEVEL_DUPLICATE);
-    return new expairseq(*this);
-}
+       archive_node::archive_node_cit first = n.find_first("rest");
+       archive_node::archive_node_cit last = n.find_last("coeff");
+       ++last;
+       seq.reserve((last-first)/2);
 
-bool expairseq::info(unsigned inf) const
-{
-    return basic::info(inf);
-}
+       for (archive_node::archive_node_cit loc = first; loc < last;) {
+               ex rest;
+               ex coeff;
+               n.find_ex_by_loc(loc++, rest, sym_lst);
+               n.find_ex_by_loc(loc++, coeff, sym_lst);
+               seq.push_back(expair(rest, coeff));
+       }
 
-int expairseq::nops() const
-{
-    if (overall_coeff.is_equal(default_overall_coeff())) {
-        return seq.size();
-    }
-    return seq.size()+1;
-}
+       n.find_ex("overall_coeff", overall_coeff, sym_lst);
 
-ex expairseq::op(int const i) const
-{
-    if (unsigned(i)<seq.size()) {
-        return recombine_pair_to_ex(seq[i]);
-    }
-    ASSERT(!overall_coeff.is_equal(default_overall_coeff()));
-    return overall_coeff;
+       canonicalize();
+       GINAC_ASSERT(is_canonical());
 }
 
-ex & expairseq::let_op(int const i)
+void expairseq::archive(archive_node &n) const
 {
-    throw(std::logic_error("let_op not defined for expairseq and derived classes (add,mul,...)"));
+       inherited::archive(n);
+       epvector::const_iterator i = seq.begin(), iend = seq.end();
+       while (i != iend) {
+               n.add_ex("rest", i->rest);
+               n.add_ex("coeff", i->coeff);
+               ++i;
+       }
+       n.add_ex("overall_coeff", overall_coeff);
 }
 
-ex expairseq::eval(int level) const
-{
-    if ((level==1)&&(flags & status_flags::evaluated)) {
-        return *this;
-    }
-
-    epvector * vp=evalchildren(level);
-    if (vp==0) {
-        return this->hold();
-    }
-
-    return (new expairseq(vp,overall_coeff))
-               ->setflag(status_flags::dynallocated |
-                         status_flags::evaluated );
-}
+DEFAULT_UNARCHIVE(expairseq)
 
-ex expairseq::evalf(int level) const
-{
-    return thisexpairseq(evalfchildren(level),overall_coeff);
-}
+//////////
+// functions overriding virtual functions from base classes
+//////////
 
-ex expairseq::normal(lst &sym_lst, lst &repl_lst, int level) const
-{
-    ex n=thisexpairseq(normalchildren(level),overall_coeff);
-    return n.bp->basic::normal(sym_lst,repl_lst,level);
-}
+// public
 
-ex expairseq::subs(lst const & ls, lst const & lr) const
-{
-    epvector * vp=subschildren(ls,lr);
-    if (vp==0) {
-        return *this;
-    }
-    return thisexpairseq(vp,overall_coeff);
+void expairseq::do_print(const print_context & c, unsigned level) const
+{
+       c.s << "[[";
+       printseq(c, ',', precedence(), level);
+       c.s << "]]";
+}
+
+void expairseq::do_print_tree(const print_tree & c, unsigned level) const
+{
+       c.s << std::string(level, ' ') << class_name() << " @" << this
+           << std::hex << ", hash=0x" << hashvalue << ", flags=0x" << flags << std::dec
+           << ", nops=" << nops()
+           << std::endl;
+       size_t num = seq.size();
+       for (size_t i=0; i<num; ++i) {
+               seq[i].rest.print(c, level + c.delta_indent);
+               seq[i].coeff.print(c, level + c.delta_indent);
+               if (i != num - 1)
+                       c.s << std::string(level + c.delta_indent, ' ') << "-----" << std::endl;
+       }
+       if (!overall_coeff.is_equal(default_overall_coeff())) {
+               c.s << std::string(level + c.delta_indent, ' ') << "-----" << std::endl
+                   << std::string(level + c.delta_indent, ' ') << "overall_coeff" << std::endl;
+               overall_coeff.print(c, level + c.delta_indent);
+       }
+       c.s << std::string(level + c.delta_indent,' ') << "=====" << std::endl;
+#if EXPAIRSEQ_USE_HASHTAB
+       c.s << std::string(level + c.delta_indent,' ')
+           << "hashtab size " << hashtabsize << std::endl;
+       if (hashtabsize == 0) return;
+#define MAXCOUNT 5
+       unsigned count[MAXCOUNT+1];
+       for (int i=0; i<MAXCOUNT+1; ++i)
+               count[i] = 0;
+       unsigned this_bin_fill;
+       unsigned cum_fill_sq = 0;
+       unsigned cum_fill = 0;
+       for (unsigned i=0; i<hashtabsize; ++i) {
+               this_bin_fill = 0;
+               if (hashtab[i].size() > 0) {
+                       c.s << std::string(level + c.delta_indent, ' ')
+                           << "bin " << i << " with entries ";
+                       for (epplist::const_iterator it=hashtab[i].begin();
+                            it!=hashtab[i].end(); ++it) {
+                               c.s << *it-seq.begin() << " ";
+                               ++this_bin_fill;
+                       }
+                       c.s << std::endl;
+                       cum_fill += this_bin_fill;
+                       cum_fill_sq += this_bin_fill*this_bin_fill;
+               }
+               if (this_bin_fill<MAXCOUNT)
+                       ++count[this_bin_fill];
+               else
+                       ++count[MAXCOUNT];
+       }
+       unsigned fact = 1;
+       double cum_prob = 0;
+       double lambda = (1.0*seq.size()) / hashtabsize;
+       for (int k=0; k<MAXCOUNT; ++k) {
+               if (k>0)
+                       fact *= k;
+               double prob = std::pow(lambda,k)/fact * std::exp(-lambda);
+               cum_prob += prob;
+               c.s << std::string(level + c.delta_indent, ' ') << "bins with " << k << " entries: "
+                   << int(1000.0*count[k]/hashtabsize)/10.0 << "% (expected: "
+                   << int(prob*1000)/10.0 << ")" << std::endl;
+       }
+       c.s << std::string(level + c.delta_indent, ' ') << "bins with more entries: "
+           << int(1000.0*count[MAXCOUNT]/hashtabsize)/10.0 << "% (expected: "
+           << int((1-cum_prob)*1000)/10.0 << ")" << std::endl;
+
+       c.s << std::string(level + c.delta_indent, ' ') << "variance: "
+           << 1.0/hashtabsize*cum_fill_sq-(1.0/hashtabsize*cum_fill)*(1.0/hashtabsize*cum_fill)
+           << std::endl;
+       c.s << std::string(level + c.delta_indent, ' ') << "average fill: "
+           << (1.0*cum_fill)/hashtabsize
+           << " (should be equal to " << (1.0*seq.size())/hashtabsize << ")" << std::endl;
+#endif // EXPAIRSEQ_USE_HASHTAB
 }
 
-// protected
-
-int expairseq::compare_same_type(basic const & other) const
+bool expairseq::info(unsigned inf) const
 {
-    ASSERT(is_of_type(other, expairseq));
-    expairseq const & o=static_cast<expairseq const &>(const_cast<basic &>(other));
-
-    int cmpval;
-    
-    // compare number of elements
-    if (seq.size() != o.seq.size()) {
-        return (seq.size()<o.seq.size()) ? -1 : 1;
-    }
-
-    // compare overall_coeff
-    cmpval=overall_coeff.compare(o.overall_coeff);
-    if (cmpval!=0) return cmpval;
-
-    //if (seq.size()==0) return 0; // empty expairseq's are equal
-
-#ifdef EXPAIRSEQ_USE_HASHTAB
-    ASSERT(hashtabsize==o.hashtabsize);
-    if (hashtabsize==0) {
-#endif // def EXPAIRSEQ_USE_HASHTAB
-        epvector::const_iterator cit1=seq.begin();
-        epvector::const_iterator cit2=o.seq.begin();
-        epvector::const_iterator last1=seq.end();
-        epvector::const_iterator last2=o.seq.end();
-        
-        for (; (cit1!=last1)&&(cit2!=last2); ++cit1, ++cit2) {
-            cmpval=(*cit1).compare(*cit2);
-            if (cmpval!=0) return cmpval;
-        }
-
-        ASSERT(cit1==last1);
-        ASSERT(cit2==last2);
-        
-        return 0;
-#ifdef EXPAIRSEQ_USE_HASHTAB
-    }
-
-    // compare number of elements in each hashtab entry
-    for (unsigned i=0; i<hashtabsize; ++i) {
-        unsigned cursize=hashtab[i].size();
-        if (cursize != o.hashtab[i].size()) {
-            return (cursize < o.hashtab[i].size()) ? -1 : 1;
-        }
-    }
-    
-    // compare individual (sorted) hashtab entries
-    for (unsigned i=0; i<hashtabsize; ++i) {
-        unsigned sz=hashtab[i].size();
-        if (sz>0) {
-            epplist const & eppl1=hashtab[i];
-            epplist const & eppl2=o.hashtab[i];
-            epplist::const_iterator it1=eppl1.begin();
-            epplist::const_iterator it2=eppl2.begin();
-            while (it1!=eppl1.end()) {
-                cmpval=(*(*it1)).compare(*(*it2));
-                if (cmpval!=0) return cmpval;
-                ++it1;
-                ++it2;
-            }
-        }
-    }
-    
-    return 0; // equal
-#endif // def EXPAIRSEQ_USE_HASHTAB
-}
-
-bool expairseq::is_equal_same_type(basic const & other) const
+       switch(inf) {
+               case info_flags::expanded:
+                       return (flags & status_flags::expanded);
+               case info_flags::has_indices: {
+                       if (flags & status_flags::has_indices)
+                               return true;
+                       else if (flags & status_flags::has_no_indices)
+                               return false;
+                       for (epvector::const_iterator i = seq.begin(); i != seq.end(); ++i) {
+                               if (i->rest.info(info_flags::has_indices)) {
+                                       this->setflag(status_flags::has_indices);
+                                       this->clearflag(status_flags::has_no_indices);
+                                       return true;
+                               }
+                       }
+                       this->clearflag(status_flags::has_indices);
+                       this->setflag(status_flags::has_no_indices);
+                       return false;
+               }
+       }
+       return inherited::info(inf);
+}
+
+size_t expairseq::nops() const
+{
+       if (overall_coeff.is_equal(default_overall_coeff()))
+               return seq.size();
+       else
+               return seq.size()+1;
+}
+
+ex expairseq::op(size_t i) const
+{
+       if (i < seq.size())
+               return recombine_pair_to_ex(seq[i]);
+       GINAC_ASSERT(!overall_coeff.is_equal(default_overall_coeff()));
+       return overall_coeff;
+}
+
+ex expairseq::map(map_function &f) const
+{
+       std::auto_ptr<epvector> v(new epvector);
+       v->reserve(seq.size()+1);
+
+       epvector::const_iterator cit = seq.begin(), last = seq.end();
+       while (cit != last) {
+               v->push_back(split_ex_to_pair(f(recombine_pair_to_ex(*cit))));
+               ++cit;
+       }
+
+       if (overall_coeff.is_equal(default_overall_coeff()))
+               return thisexpairseq(v, default_overall_coeff(), true);
+       else {
+               ex newcoeff = f(overall_coeff);
+               if(is_a<numeric>(newcoeff))
+                       return thisexpairseq(v, newcoeff, true);
+               else {
+                       v->push_back(split_ex_to_pair(newcoeff));
+                       return thisexpairseq(v, default_overall_coeff(), true);
+               }
+       }
+}
+
+/** Perform coefficient-wise automatic term rewriting rules in this class. */
+ex expairseq::eval(int level) const
 {
-    expairseq const & o=dynamic_cast<expairseq const &>(const_cast<basic &>(other));
-
-    // compare number of elements
-    if (seq.size() != o.seq.size()) return false;
-
-    // compare overall_coeff
-    if (!overall_coeff.is_equal(o.overall_coeff)) return false;
-
-#ifdef EXPAIRSEQ_USE_HASHTAB
-    // compare number of elements in each hashtab entry
-    if (hashtabsize!=o.hashtabsize) {
-        cout << "this:" << endl;
-        printtree(cout,0);
-        cout << "other:" << endl;
-        other.printtree(cout,0);
-    }
-        
-    ASSERT(hashtabsize==o.hashtabsize);
-    
-    if (hashtabsize==0) {
-#endif // def EXPAIRSEQ_USE_HASHTAB
-        epvector::const_iterator cit1=seq.begin();
-        epvector::const_iterator cit2=o.seq.begin();
-        epvector::const_iterator last1=seq.end();
-        
-        while (cit1!=last1) {
-            if (!(*cit1).is_equal(*cit2)) return false;
-            ++cit1;
-            ++cit2;
-        }
-        
-        return true;
-#ifdef EXPAIRSEQ_USE_HASHTAB
-    }
-
-    for (unsigned i=0; i<hashtabsize; ++i) {
-        if (hashtab[i].size() != o.hashtab[i].size()) return false;
-    }
-
-    // compare individual sorted hashtab entries
-    for (unsigned i=0; i<hashtabsize; ++i) {
-        unsigned sz=hashtab[i].size();
-        if (sz>0) {
-            epplist const & eppl1=hashtab[i];
-            epplist const & eppl2=o.hashtab[i];
-            epplist::const_iterator it1=eppl1.begin();
-            epplist::const_iterator it2=eppl2.begin();
-            while (it1!=eppl1.end()) {
-                if (!(*(*it1)).is_equal(*(*it2))) return false;
-                ++it1;
-                ++it2;
-            }
-        }
-    }
-
-    return true;
-#endif // def EXPAIRSEQ_USE_HASHTAB
+       if ((level==1) && (flags &status_flags::evaluated))
+               return *this;
+       
+       std::auto_ptr<epvector> vp = evalchildren(level);
+       if (vp.get() == 0)
+               return this->hold();
+       
+       return (new expairseq(vp, overall_coeff))->setflag(status_flags::dynallocated | status_flags::evaluated);
+}
+
+epvector* conjugateepvector(const epvector&epv)
+{
+       epvector *newepv = 0;
+       for (epvector::const_iterator i=epv.begin(); i!=epv.end(); ++i) {
+               if(newepv) {
+                       newepv->push_back(i->conjugate());
+                       continue;
+               }
+               expair x = i->conjugate();
+               if (x.is_equal(*i)) {
+                       continue;
+               }
+               newepv = new epvector;
+               newepv->reserve(epv.size());
+               for (epvector::const_iterator j=epv.begin(); j!=i; ++j) {
+                       newepv->push_back(*j);
+               }
+               newepv->push_back(x);
+       }
+       return newepv;
+}
+
+ex expairseq::conjugate() const
+{
+       epvector* newepv = conjugateepvector(seq);
+       ex x = overall_coeff.conjugate();
+       if (!newepv && are_ex_trivially_equal(x, overall_coeff)) {
+               return *this;
+       }
+       ex result = thisexpairseq(newepv ? *newepv : seq, x);
+       if (newepv) {
+               delete newepv;
+       }
+       return result;
+}
+
+bool expairseq::is_polynomial(const ex & var) const
+{
+       if (!is_exactly_a<add>(*this) && !is_exactly_a<mul>(*this))
+               return basic::is_polynomial(var);
+       for (epvector::const_iterator i=seq.begin(); i!=seq.end(); ++i) {
+               if (!(i->rest).is_polynomial(var))
+                       return false;
+       }
+       return true;
+}
+
+bool expairseq::match(const ex & pattern, exmap & repl_lst) const
+{
+       // This differs from basic::match() because we want "a+b+c+d" to
+       // match "d+*+b" with "*" being "a+c", and we want to honor commutativity
+
+       if (typeid(*this) == typeid(ex_to<basic>(pattern))) {
+
+               // Check whether global wildcard (one that matches the "rest of the
+               // expression", like "*" above) is present
+               bool has_global_wildcard = false;
+               ex global_wildcard;
+               for (size_t i=0; i<pattern.nops(); i++) {
+                       if (is_exactly_a<wildcard>(pattern.op(i))) {
+                               has_global_wildcard = true;
+                               global_wildcard = pattern.op(i);
+                               break;
+                       }
+               }
+
+               // Unfortunately, this is an O(N^2) operation because we can't
+               // sort the pattern in a useful way...
+
+               // Chop into terms
+               exvector ops;
+               ops.reserve(nops());
+               for (size_t i=0; i<nops(); i++)
+                       ops.push_back(op(i));
+
+               // Now, for every term of the pattern, look for a matching term in
+               // the expression and remove the match
+               for (size_t i=0; i<pattern.nops(); i++) {
+                       ex p = pattern.op(i);
+                       if (has_global_wildcard && p.is_equal(global_wildcard))
+                               continue;
+                       exvector::iterator it = ops.begin(), itend = ops.end();
+                       while (it != itend) {
+                               if (it->match(p, repl_lst)) {
+                                       ops.erase(it);
+                                       goto found;
+                               }
+                               ++it;
+                       }
+                       return false; // no match found
+found:         ;
+               }
+
+               if (has_global_wildcard) {
+
+                       // Assign all the remaining terms to the global wildcard (unless
+                       // it has already been matched before, in which case the matches
+                       // must be equal)
+                       size_t num = ops.size();
+                       std::auto_ptr<epvector> vp(new epvector);
+                       vp->reserve(num);
+                       for (size_t i=0; i<num; i++)
+                               vp->push_back(split_ex_to_pair(ops[i]));
+                       ex rest = thisexpairseq(vp, default_overall_coeff());
+                       for (exmap::const_iterator it = repl_lst.begin(); it != repl_lst.end(); ++it) {
+                               if (it->first.is_equal(global_wildcard))
+                                       return rest.is_equal(it->second);
+                       }
+                       repl_lst[global_wildcard] = rest;
+                       return true;
+
+               } else {
+
+                       // No global wildcard, then the match fails if there are any
+                       // unmatched terms left
+                       return ops.empty();
+               }
+       }
+       return inherited::match(pattern, repl_lst);
+}
+
+ex expairseq::subs(const exmap & m, unsigned options) const
+{
+       std::auto_ptr<epvector> vp = subschildren(m, options);
+       if (vp.get())
+               return ex_to<basic>(thisexpairseq(vp, overall_coeff, true));
+       else if ((options & subs_options::algebraic) && is_exactly_a<mul>(*this))
+               return static_cast<const mul *>(this)->algebraic_subs_mul(m, options);
+       else
+               return subs_one_level(m, options);
 }
 
-unsigned expairseq::return_type(void) const
-{
-    return return_types::noncommutative_composite;
-}
+// protected
 
-unsigned expairseq::calchash(void) const
-{
-    unsigned v=golden_ratio_hash(tinfo());
-    epvector::const_iterator last=seq.end();
-    for (epvector::const_iterator cit=seq.begin(); cit!=last; ++cit) {
-#ifndef EXPAIRSEQ_USE_HASHTAB
-        v=rotate_left_31(v); // rotation would spoil commutativity
-#endif // ndef EXPAIRSEQ_USE_HASHTAB
-        v ^= (*cit).rest.gethash();
-    }
-
-    v ^= overall_coeff.gethash();
-    v=v & 0x7FFFFFFFU;
-    
-    // store calculated hash value only if object is already evaluated
-    if (flags & status_flags::evaluated) {
-        setflag(status_flags::hash_calculated);
-        hashvalue=v;
-    }
-
-    return v;
+int expairseq::compare_same_type(const basic &other) const
+{
+       GINAC_ASSERT(is_a<expairseq>(other));
+       const expairseq &o = static_cast<const expairseq &>(other);
+       
+       int cmpval;
+       
+       // compare number of elements
+       if (seq.size() != o.seq.size())
+               return (seq.size()<o.seq.size()) ? -1 : 1;
+       
+       // compare overall_coeff
+       cmpval = overall_coeff.compare(o.overall_coeff);
+       if (cmpval!=0)
+               return cmpval;
+       
+#if EXPAIRSEQ_USE_HASHTAB
+       GINAC_ASSERT(hashtabsize==o.hashtabsize);
+       if (hashtabsize==0) {
+#endif // EXPAIRSEQ_USE_HASHTAB
+               epvector::const_iterator cit1 = seq.begin();
+               epvector::const_iterator cit2 = o.seq.begin();
+               epvector::const_iterator last1 = seq.end();
+               epvector::const_iterator last2 = o.seq.end();
+               
+               for (; (cit1!=last1)&&(cit2!=last2); ++cit1, ++cit2) {
+                       cmpval = (*cit1).compare(*cit2);
+                       if (cmpval!=0) return cmpval;
+               }
+               
+               GINAC_ASSERT(cit1==last1);
+               GINAC_ASSERT(cit2==last2);
+               
+               return 0;
+#if EXPAIRSEQ_USE_HASHTAB
+       }
+       
+       // compare number of elements in each hashtab entry
+       for (unsigned i=0; i<hashtabsize; ++i) {
+               unsigned cursize=hashtab[i].size();
+               if (cursize != o.hashtab[i].size())
+                       return (cursize < o.hashtab[i].size()) ? -1 : 1;
+       }
+       
+       // compare individual (sorted) hashtab entries
+       for (unsigned i=0; i<hashtabsize; ++i) {
+               unsigned sz = hashtab[i].size();
+               if (sz>0) {
+                       const epplist &eppl1 = hashtab[i];
+                       const epplist &eppl2 = o.hashtab[i];
+                       epplist::const_iterator it1 = eppl1.begin();
+                       epplist::const_iterator it2 = eppl2.begin();
+                       while (it1!=eppl1.end()) {
+                               cmpval = (*(*it1)).compare(*(*it2));
+                               if (cmpval!=0)
+                                       return cmpval;
+                               ++it1;
+                               ++it2;
+                       }
+               }
+       }
+       
+       return 0; // equal
+#endif // EXPAIRSEQ_USE_HASHTAB
+}
+
+bool expairseq::is_equal_same_type(const basic &other) const
+{
+       const expairseq &o = static_cast<const expairseq &>(other);
+       
+       // compare number of elements
+       if (seq.size()!=o.seq.size())
+               return false;
+       
+       // compare overall_coeff
+       if (!overall_coeff.is_equal(o.overall_coeff))
+               return false;
+       
+#if EXPAIRSEQ_USE_HASHTAB
+       // compare number of elements in each hashtab entry
+       if (hashtabsize!=o.hashtabsize) {
+               std::cout << "this:" << std::endl;
+               print(print_tree(std::cout));
+               std::cout << "other:" << std::endl;
+               other.print(print_tree(std::cout));
+       }
+               
+       GINAC_ASSERT(hashtabsize==o.hashtabsize);
+       
+       if (hashtabsize==0) {
+#endif // EXPAIRSEQ_USE_HASHTAB
+               epvector::const_iterator cit1 = seq.begin();
+               epvector::const_iterator cit2 = o.seq.begin();
+               epvector::const_iterator last1 = seq.end();
+               
+               while (cit1!=last1) {
+                       if (!(*cit1).is_equal(*cit2)) return false;
+                       ++cit1;
+                       ++cit2;
+               }
+               
+               return true;
+#if EXPAIRSEQ_USE_HASHTAB
+       }
+       
+       for (unsigned i=0; i<hashtabsize; ++i) {
+               if (hashtab[i].size() != o.hashtab[i].size())
+                       return false;
+       }
+
+       // compare individual sorted hashtab entries
+       for (unsigned i=0; i<hashtabsize; ++i) {
+               unsigned sz = hashtab[i].size();
+               if (sz>0) {
+                       const epplist &eppl1 = hashtab[i];
+                       const epplist &eppl2 = o.hashtab[i];
+                       epplist::const_iterator it1 = eppl1.begin();
+                       epplist::const_iterator it2 = eppl2.begin();
+                       while (it1!=eppl1.end()) {
+                               if (!(*(*it1)).is_equal(*(*it2))) return false;
+                               ++it1;
+                               ++it2;
+                       }
+               }
+       }
+       
+       return true;
+#endif // EXPAIRSEQ_USE_HASHTAB
+}
+
+unsigned expairseq::return_type() const
+{
+       return return_types::noncommutative_composite;
+}
+
+unsigned expairseq::calchash() const
+{
+       unsigned v = golden_ratio_hash((p_int)this->tinfo());
+       epvector::const_iterator i = seq.begin();
+       const epvector::const_iterator end = seq.end();
+       while (i != end) {
+               v ^= i->rest.gethash();
+#if !EXPAIRSEQ_USE_HASHTAB
+               // rotation spoils commutativity!
+               v = rotate_left(v);
+               v ^= i->coeff.gethash();
+#endif // !EXPAIRSEQ_USE_HASHTAB
+               ++i;
+       }
+
+       v ^= overall_coeff.gethash();
+
+       // store calculated hash value only if object is already evaluated
+       if (flags &status_flags::evaluated) {
+               setflag(status_flags::hash_calculated);
+               hashvalue = v;
+       }
+       
+       return v;
 }
 
 ex expairseq::expand(unsigned options) const
 {
-    epvector * vp=expandchildren(options);
-    if (vp==0) {
-        return *this;
-    }
-    return thisexpairseq(vp,overall_coeff);
+       std::auto_ptr<epvector> vp = expandchildren(options);
+       if (vp.get())
+               return thisexpairseq(vp, overall_coeff);
+       else {
+               // The terms have not changed, so it is safe to declare this expanded
+               return (options == 0) ? setflag(status_flags::expanded) : *this;
+       }
 }
 
 //////////
@@ -395,1231 +656,1102 @@ ex expairseq::expand(unsigned options) const
 
 // protected
 
-ex expairseq::thisexpairseq(epvector const & v,ex const & oc) const
+/** Create an object of this type.
+ *  This method works similar to a constructor.  It is useful because expairseq
+ *  has (at least) two possible different semantics but we want to inherit
+ *  methods thus avoiding code duplication.  Sometimes a method in expairseq
+ *  has to create a new one of the same semantics, which cannot be done by a
+ *  ctor because the name (add, mul,...) is unknown on the expaiseq level.  In
+ *  order for this trick to work a derived class must of course override this
+ *  definition. */
+ex expairseq::thisexpairseq(const epvector &v, const ex &oc, bool do_index_renaming) const
 {
-    return expairseq(v,oc);
+       return expairseq(v, oc, do_index_renaming);
 }
 
-ex expairseq::thisexpairseq(epvector * vp, ex const & oc) const
+ex expairseq::thisexpairseq(std::auto_ptr<epvector> vp, const ex &oc, bool do_index_renaming) const
 {
-    return expairseq(vp,oc);
+       return expairseq(vp, oc, do_index_renaming);
 }
 
-expair expairseq::split_ex_to_pair(ex const & e) const
+void expairseq::printpair(const print_context & c, const expair & p, unsigned upper_precedence) const
 {
-    return expair(e,exONE());
+       c.s << "[[";
+       p.rest.print(c, precedence());
+       c.s << ",";
+       p.coeff.print(c, precedence());
+       c.s << "]]";
 }
 
-expair expairseq::combine_ex_with_coeff_to_pair(ex const & e,
-                                                ex const & c) const
+void expairseq::printseq(const print_context & c, char delim,
+                         unsigned this_precedence,
+                         unsigned upper_precedence) const
 {
-    ASSERT(is_ex_exactly_of_type(c,numeric));
-
-    return expair(e,c);
+       if (this_precedence <= upper_precedence)
+               c.s << "(";
+       epvector::const_iterator it, it_last = seq.end() - 1;
+       for (it=seq.begin(); it!=it_last; ++it) {
+               printpair(c, *it, this_precedence);
+               c.s << delim;
+       }
+       printpair(c, *it, this_precedence);
+       if (!overall_coeff.is_equal(default_overall_coeff())) {
+               c.s << delim;
+               overall_coeff.print(c, this_precedence);
+       }
+       
+       if (this_precedence <= upper_precedence)
+               c.s << ")";
 }
 
-expair expairseq::combine_pair_with_coeff_to_pair(expair const & p,
-                                                  ex const & c) const
-{
-    ASSERT(is_ex_exactly_of_type(p.coeff,numeric));
-    ASSERT(is_ex_exactly_of_type(c,numeric));
-    
-    return expair(p.rest,ex_to_numeric(p.coeff).mul_dyn(ex_to_numeric(c)));
-}
-
-ex expairseq::recombine_pair_to_ex(expair const & p) const
-{
-    return lst(p.rest,p.coeff);
-}
-
-bool expairseq::expair_needs_further_processing(epp it)
-{
-    return false;
-}
-
-ex expairseq::default_overall_coeff(void) const
-{
-    return exZERO();
-}
 
-void expairseq::combine_overall_coeff(ex const & c)
+/** Form an expair from an ex, using the corresponding semantics.
+ *  @see expairseq::recombine_pair_to_ex() */
+expair expairseq::split_ex_to_pair(const ex &e) const
 {
-    ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
-    ASSERT(is_ex_exactly_of_type(c,numeric));
-    overall_coeff = ex_to_numeric(overall_coeff).add_dyn(ex_to_numeric(c));
+       return expair(e,_ex1);
 }
 
-void expairseq::combine_overall_coeff(ex const & c1, ex const & c2)
-{
-    ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
-    ASSERT(is_ex_exactly_of_type(c1,numeric));
-    ASSERT(is_ex_exactly_of_type(c2,numeric));
-    overall_coeff = ex_to_numeric(overall_coeff).
-                        add_dyn(ex_to_numeric(c1).mul(ex_to_numeric(c2)));
-}
 
-bool expairseq::can_make_flat(expair const & p) const
+expair expairseq::combine_ex_with_coeff_to_pair(const ex &e,
+                                                const ex &c) const
 {
-    return true;
+       GINAC_ASSERT(is_exactly_a<numeric>(c));
+       
+       return expair(e,c);
 }
 
-    
-//////////
-// non-virtual functions in this class
-//////////
 
-void expairseq::construct_from_2_ex_via_exvector(ex const & lh, ex const & rh)
+expair expairseq::combine_pair_with_coeff_to_pair(const expair &p,
+                                                  const ex &c) const
 {
-    exvector v;
-    v.reserve(2);
-    v.push_back(lh);
-    v.push_back(rh);
-    construct_from_exvector(v);
-#ifdef EXPAIRSEQ_USE_HASHTAB
-    ASSERT((hashtabsize==0)||(hashtabsize>=minhashtabsize));
-    ASSERT(hashtabsize==calc_hashtabsize(seq.size()));
-#endif // def EXPAIRSEQ_USE_HASHTAB
+       GINAC_ASSERT(is_exactly_a<numeric>(p.coeff));
+       GINAC_ASSERT(is_exactly_a<numeric>(c));
+       
+       return expair(p.rest,ex_to<numeric>(p.coeff).mul_dyn(ex_to<numeric>(c)));
 }
 
-void expairseq::construct_from_2_ex(ex const & lh, ex const & rh)
-{
-    if (lh.bp->tinfo()==tinfo()) {
-       if (rh.bp->tinfo()==tinfo()) {
-#ifdef EXPAIRSEQ_USE_HASHTAB
-           unsigned totalsize=ex_to_expairseq(lh).seq.size()+
-                              ex_to_expairseq(rh).seq.size();
-           if (calc_hashtabsize(totalsize)!=0) {
-               construct_from_2_ex_via_exvector(lh,rh);
-           } else {
-#endif // def EXPAIRSEQ_USE_HASHTAB
-               construct_from_2_expairseq(ex_to_expairseq(lh),
-                                          ex_to_expairseq(rh));
-#ifdef EXPAIRSEQ_USE_HASHTAB
-           }
-#endif // def EXPAIRSEQ_USE_HASHTAB
-           return;
-       } else {
-#ifdef EXPAIRSEQ_USE_HASHTAB
-           unsigned totalsize=ex_to_expairseq(lh).seq.size()+1;
-           if (calc_hashtabsize(totalsize)!=0) {
-               construct_from_2_ex_via_exvector(lh,rh);
-           } else {
-#endif // def EXPAIRSEQ_USE_HASHTAB
-               construct_from_expairseq_ex(ex_to_expairseq(lh),rh);
-#ifdef EXPAIRSEQ_USE_HASHTAB
-           }
-#endif // def EXPAIRSEQ_USE_HASHTAB
-           return;
-       }
-    } else if (rh.bp->tinfo()==tinfo()) {
-#ifdef EXPAIRSEQ_USE_HASHTAB
-        unsigned totalsize=ex_to_expairseq(rh).seq.size()+1;
-        if (calc_hashtabsize(totalsize)!=0) {
-            construct_from_2_ex_via_exvector(lh,rh);
-        } else {
-#endif // def EXPAIRSEQ_USE_HASHTAB
-            construct_from_expairseq_ex(ex_to_expairseq(rh),lh);
-#ifdef EXPAIRSEQ_USE_HASHTAB
-        }
-#endif // def EXPAIRSEQ_USE_HASHTAB
-        return;
-    }
-
-#ifdef EXPAIRSEQ_USE_HASHTAB
-    if (calc_hashtabsize(2)!=0) {
-        construct_from_2_ex_via_exvector(lh,rh);
-        return;
-    }
-    hashtabsize=0;
-#endif // def EXPAIRSEQ_USE_HASHTAB
-    
-    if (is_ex_exactly_of_type(lh,numeric)) {
-        if (is_ex_exactly_of_type(rh,numeric)) {
-            combine_overall_coeff(lh);
-            combine_overall_coeff(rh);
-        } else {
-            combine_overall_coeff(lh);
-            seq.push_back(split_ex_to_pair(rh));
-        }
-    } else {
-        if (is_ex_exactly_of_type(rh,numeric)) {
-            combine_overall_coeff(rh);
-            seq.push_back(split_ex_to_pair(lh));
-        } else {
-            expair p1=split_ex_to_pair(lh);
-            expair p2=split_ex_to_pair(rh);
-
-            int cmpval=p1.rest.compare(p2.rest);
-            if (cmpval==0) {
-                p1.coeff=ex_to_numeric(p1.coeff).add_dyn(ex_to_numeric(p2.coeff));
-                if (!ex_to_numeric(p1.coeff).is_zero()) {
-                    // no further processing is necessary, since this
-                    // one element will usually be recombined in eval()
-                    seq.push_back(p1);
-                }
-            } else {
-                seq.reserve(2);
-                if (cmpval<0) {
-                    seq.push_back(p1);
-                    seq.push_back(p2);
-                } else {
-                    seq.push_back(p2);
-                    seq.push_back(p1);
-                }
-            }
-        }
-    }
-}
 
-void expairseq::construct_from_2_expairseq(expairseq const & s1,
-                                           expairseq const & s2)
+/** Form an ex out of an expair, using the corresponding semantics.
+ *  @see expairseq::split_ex_to_pair() */
+ex expairseq::recombine_pair_to_ex(const expair &p) const
 {
-    combine_overall_coeff(s1.overall_coeff);
-    combine_overall_coeff(s2.overall_coeff);
-
-    epvector::const_iterator first1=s1.seq.begin();
-    epvector::const_iterator last1=s1.seq.end();
-    epvector::const_iterator first2=s2.seq.begin();
-    epvector::const_iterator last2=s2.seq.end();
-
-    seq.reserve(s1.seq.size()+s2.seq.size());
-
-    bool needs_further_processing=false;
-    
-    while (first1!=last1 && first2!=last2) {
-        int cmpval=(*first1).rest.compare((*first2).rest);
-        if (cmpval==0) {
-            // combine terms
-            numeric const & newcoeff=ex_to_numeric((*first1).coeff).
-                                     add(ex_to_numeric((*first2).coeff));
-            if (!newcoeff.is_zero()) {
-                seq.push_back(expair((*first1).rest,newcoeff));
-                if (expair_needs_further_processing(seq.end()-1)) {
-                    needs_further_processing = true;
-                }
-            }
-            ++first1;
-            ++first2;
-        } else if (cmpval<0) {
-            seq.push_back(*first1);
-            ++first1;
-        } else {
-            seq.push_back(*first2);
-            ++first2;
-        }
-    }
-    
-    while (first1!=last1) {
-        seq.push_back(*first1);
-        ++first1;
-    }
-    while (first2!=last2) {
-        seq.push_back(*first2);
-        ++first2;
-    }
-
-    if (needs_further_processing) {
-        epvector v=seq;
-        seq.clear();
-        construct_from_epvector(v);
-    }
+       return lst(p.rest,p.coeff);
 }
 
-void expairseq::construct_from_expairseq_ex(expairseq const & s,
-                                            ex const & e)
+bool expairseq::expair_needs_further_processing(epp it)
 {
-    combine_overall_coeff(s.overall_coeff);
-    if (is_ex_exactly_of_type(e,numeric)) {
-        combine_overall_coeff(e);
-        seq=s.seq;
-        return;
-    }
-
-    epvector::const_iterator first=s.seq.begin();
-    epvector::const_iterator last=s.seq.end();
-    expair p=split_ex_to_pair(e);
-
-    seq.reserve(s.seq.size()+1);
-    bool p_pushed=0;
-
-    bool needs_further_processing=false;
-
-    // merge p into s.seq
-    while (first!=last) {
-        int cmpval=(*first).rest.compare(p.rest);
-        if (cmpval==0) {
-            // combine terms
-            numeric const & newcoeff=ex_to_numeric((*first).coeff).
-                                     add(ex_to_numeric(p.coeff));
-            if (!newcoeff.is_zero()) {
-                seq.push_back(expair((*first).rest,newcoeff));
-                if (expair_needs_further_processing(seq.end()-1)) {
-                    needs_further_processing = true;
-                }
-            }
-            ++first;
-            p_pushed=1;
-            break;
-        } else if (cmpval<0) {
-            seq.push_back(*first);
-            ++first;
-        } else {
-            seq.push_back(p);
-            p_pushed=1;
-            break;
-        }
-    }
-
-    if (p_pushed) {
-        // while loop exited because p was pushed, now push rest of s.seq
-        while (first!=last) {
-            seq.push_back(*first);
-            ++first;
-        }
-    } else {
-        // while loop exited because s.seq was pushed, now push p
-        seq.push_back(p);
-    }
-
-    if (needs_further_processing) {
-        epvector v=seq;
-        seq.clear();
-        construct_from_epvector(v);
-    }
+#if EXPAIRSEQ_USE_HASHTAB
+       //#  error "FIXME: expair_needs_further_processing not yet implemented for hashtabs, sorry. A.F."
+#endif // EXPAIRSEQ_USE_HASHTAB
+       return false;
 }
 
-void expairseq::construct_from_exvector(exvector const & v)
+ex expairseq::default_overall_coeff() const
 {
-    // simplifications: +(a,+(b,c),d) -> +(a,b,c,d) (associativity)
-    //                  +(d,b,c,a) -> +(a,b,c,d) (canonicalization)
-    //                  +(...,x,*(x,c1),*(x,c2)) -> +(...,*(x,1+c1+c2)) (c1, c2 numeric())
-    //                  (same for (+,*) -> (*,^)
-
-    make_flat(v);
-#ifdef EXPAIRSEQ_USE_HASHTAB
-    combine_same_terms();
-#else
-    canonicalize();
-    combine_same_terms_sorted_seq();
-#endif // def EXPAIRSEQ_USE_HASHTAB
+       return _ex0;
 }
 
-void expairseq::construct_from_epvector(epvector const & v)
+void expairseq::combine_overall_coeff(const ex &c)
 {
-    // simplifications: +(a,+(b,c),d) -> +(a,b,c,d) (associativity)
-    //                  +(d,b,c,a) -> +(a,b,c,d) (canonicalization)
-    //                  +(...,x,*(x,c1),*(x,c2)) -> +(...,*(x,1+c1+c2)) (c1, c2 numeric())
-    //                  (same for (+,*) -> (*,^)
-
-    make_flat(v);
-#ifdef EXPAIRSEQ_USE_HASHTAB
-    combine_same_terms();
-#else
-    canonicalize();
-    combine_same_terms_sorted_seq();
-#endif // def EXPAIRSEQ_USE_HASHTAB
+       GINAC_ASSERT(is_exactly_a<numeric>(overall_coeff));
+       GINAC_ASSERT(is_exactly_a<numeric>(c));
+       overall_coeff = ex_to<numeric>(overall_coeff).add_dyn(ex_to<numeric>(c));
 }
 
-#include <iostream>
-
-void expairseq::make_flat(exvector const & v)
+void expairseq::combine_overall_coeff(const ex &c1, const ex &c2)
 {
-    exvector::const_iterator cit, citend = v.end();
-
-    // count number of operands which are of same expairseq derived type
-    // and their cumulative number of operands
-    int nexpairseqs=0;
-    int noperands=0;
-    cit=v.begin();
-    while (cit!=citend) {
-        if (cit->bp->tinfo()==tinfo()) {
-            nexpairseqs++;
-            noperands+=ex_to_expairseq(*cit).seq.size();
-        }
-        ++cit;
-    }
-
-    // reserve seq and coeffseq which will hold all operands
-    seq.reserve(v.size()+noperands-nexpairseqs);
-
-    // copy elements and split off numerical part
-    cit=v.begin();
-    while (cit!=citend) {
-        if (cit->bp->tinfo()==tinfo()) {
-            expairseq const & subseqref=ex_to_expairseq(*cit);
-            combine_overall_coeff(subseqref.overall_coeff);
-            epvector::const_iterator cit_s=subseqref.seq.begin();
-            while (cit_s!=subseqref.seq.end()) {
-                seq.push_back(*cit_s);
-                ++cit_s;
-            }
-        } else {
-            if (is_ex_exactly_of_type(*cit,numeric)) {
-                combine_overall_coeff(*cit);
-            } else {
-                seq.push_back(split_ex_to_pair(*cit));
-            }
-        }
-        ++cit;
-    }
-
-    /*
-    cout << "after make flat" << endl;
-    for (epvector::const_iterator cit=seq.begin(); cit!=seq.end(); ++cit) {
-        (*cit).printraw(cout);
-    }
-    cout << endl;
-    cout.flush();
-    */
+       GINAC_ASSERT(is_exactly_a<numeric>(overall_coeff));
+       GINAC_ASSERT(is_exactly_a<numeric>(c1));
+       GINAC_ASSERT(is_exactly_a<numeric>(c2));
+       overall_coeff = ex_to<numeric>(overall_coeff).
+                       add_dyn(ex_to<numeric>(c1).mul(ex_to<numeric>(c2)));
 }
 
-void expairseq::make_flat(epvector const & v)
+bool expairseq::can_make_flat(const expair &p) const
 {
-    epvector::const_iterator cit, citend = v.end();
-
-    // count number of operands which are of same expairseq derived type
-    // and their cumulative number of operands
-    int nexpairseqs=0;
-    int noperands=0;
-    cit=v.begin();
-    while (cit!=citend) {
-        if (cit->rest.bp->tinfo()==tinfo()) {
-            nexpairseqs++;
-            noperands+=ex_to_expairseq((*cit).rest).seq.size();
-        }
-        ++cit;
-    }
-
-    // reserve seq and coeffseq which will hold all operands
-    seq.reserve(v.size()+noperands-nexpairseqs);
-
-    // copy elements and split off numerical part
-    cit=v.begin();
-    while (cit!=citend) {
-        if ((cit->rest.bp->tinfo()==tinfo())&&can_make_flat(*cit)) {
-            expairseq const & subseqref=ex_to_expairseq((*cit).rest);
-            combine_overall_coeff(ex_to_numeric(subseqref.overall_coeff),
-                                  ex_to_numeric((*cit).coeff));
-            epvector::const_iterator cit_s=subseqref.seq.begin();
-            while (cit_s!=subseqref.seq.end()) {
-                seq.push_back(expair((*cit_s).rest,
-                              ex_to_numeric((*cit_s).coeff).mul_dyn(ex_to_numeric((*cit).coeff))));
-                //seq.push_back(combine_pair_with_coeff_to_pair(*cit_s,
-                //                                              (*cit).coeff));
-                ++cit_s;
-            }
-        } else {
-            if ((*cit).is_numeric_with_coeff_1()) {
-                combine_overall_coeff((*cit).rest);
-            //if (is_ex_exactly_of_type((*cit).rest,numeric)) {
-            //    combine_overall_coeff(recombine_pair_to_ex(*cit));
-            } else {
-                seq.push_back(*cit);
-            }
-        }
-        ++cit;
-    }
+       return true;
 }
 
-epvector * expairseq::bubblesort(epvector::iterator itbegin, epvector::iterator itend)
-{
-    unsigned n=itend-itbegin;
-
-    epvector * sp=new epvector;
-    sp->reserve(n);
-
-    epvector::iterator last=itend-1;
-    for (epvector::iterator it1=itbegin; it1!=last; ++it1) {
-        for (epvector::iterator it2=it1+1; it2!=itend; ++it2) {
-            if ((*it2).rest.compare((*it1).rest)<0) {
-                iter_swap(it1,it2);
-            }
-        }
-        sp->push_back(*it1);
-    }
-    sp->push_back(*last);
-    return sp;
-}
 
-epvector * expairseq::mergesort(epvector::iterator itbegin, epvector::iterator itend)
-{
-    unsigned n=itend-itbegin;
-    /*
-    if (n==1) {
-        epvector * sp=new epvector;
-        sp->push_back(*itbegin);
-        return sp;
-    }
-    */
-    if (n<16) return bubblesort(itbegin, itend);
-    unsigned m=n/2;
-    
-    epvector * s1p=mergesort(itbegin, itbegin+m);
-    epvector * s2p=mergesort(itbegin+m, itend);
-
-    epvector * sp=new epvector;
-    sp->reserve(s1p->size()+s2p->size());
-
-    epvector::iterator first1=s1p->begin();
-    epvector::iterator last1=s1p->end();
-
-    epvector::iterator first2=s2p->begin();
-    epvector::iterator last2=s2p->end();
-    
-    while (first1 != last1 && first2 != last2) {
-        if ((*first1).rest.compare((*first2).rest)<0) {
-            sp->push_back(*first1);
-            ++first1;
-        } else {
-            sp->push_back(*first2);
-            ++first2;
-        }
-    }
-
-    if (first1 != last1) {
-        while (first1 != last1) {
-            sp->push_back(*first1);
-            ++first1;
-        }
-    } else {
-        while (first2 != last2) {
-            sp->push_back(*first2);
-            ++first2;
-        }
-    }
-
-    delete s1p;
-    delete s2p;
-    
-    return sp;
-}
-            
+//////////
+// non-virtual functions in this class
+//////////
 
-void expairseq::canonicalize(void)
-{
-    // canonicalize
-    sort(seq.begin(),seq.end(),expair_is_less());
-    /*
-    sort(seq.begin(),seq.end(),expair_is_less_old());
-    if (seq.size()>1) {
-        if (is_ex_exactly_of_type((*(seq.begin())).rest,numeric)) {
-            sort(seq.begin(),seq.end(),expair_is_less());
-        } else {
-            epvector::iterator last_numeric=seq.end();
-            do {
-                last_numeric--;
-            } while (is_ex_exactly_of_type((*last_numeric).rest,numeric));
-            last_numeric++;
-            sort(last_numeric,seq.end(),expair_is_less());
-        }
-    }
-    */
-    
-    /*
-    epvector * sorted_seqp=mergesort(seq.begin(),seq.end());
-    epvector::iterator last=sorted_seqp->end();
-    epvector::iterator it2=seq.begin();
-    for (epvector::iterator it1=sorted_seqp->begin(); it1!=last; ++it1, ++it2) {
-        iter_swap(it1,it2);
-    }
-    delete sorted_seqp;
-    */
-
-    /*
-    cout << "after canonicalize" << endl;
-    for (epvector::const_iterator cit=seq.begin(); cit!=seq.end(); ++cit) {
-        (*cit).printraw(cout);
-    }
-    cout << endl;
-    cout.flush();
-    */
+void expairseq::construct_from_2_ex_via_exvector(const ex &lh, const ex &rh)
+{
+       exvector v;
+       v.reserve(2);
+       v.push_back(lh);
+       v.push_back(rh);
+       construct_from_exvector(v);
+#if EXPAIRSEQ_USE_HASHTAB
+       GINAC_ASSERT((hashtabsize==0)||(hashtabsize>=minhashtabsize));
+       GINAC_ASSERT(hashtabsize==calc_hashtabsize(seq.size()));
+#endif // EXPAIRSEQ_USE_HASHTAB
+}
+
+void expairseq::construct_from_2_ex(const ex &lh, const ex &rh)
+{
+       if (typeid(ex_to<basic>(lh)) == typeid(*this)) {
+               if (typeid(ex_to<basic>(rh)) == typeid(*this)) {
+#if EXPAIRSEQ_USE_HASHTAB
+                       unsigned totalsize = ex_to<expairseq>(lh).seq.size() +
+                                            ex_to<expairseq>(rh).seq.size();
+                       if (calc_hashtabsize(totalsize)!=0) {
+                               construct_from_2_ex_via_exvector(lh,rh);
+                       } else {
+#endif // EXPAIRSEQ_USE_HASHTAB
+                               if (is_a<mul>(lh) && lh.info(info_flags::has_indices) && 
+                                       rh.info(info_flags::has_indices)) {
+                                       ex newrh=rename_dummy_indices_uniquely(lh, rh);
+                                       construct_from_2_expairseq(ex_to<expairseq>(lh),
+                                                                  ex_to<expairseq>(newrh));
+                               }
+                               else
+                                       construct_from_2_expairseq(ex_to<expairseq>(lh),
+                                                                  ex_to<expairseq>(rh));
+#if EXPAIRSEQ_USE_HASHTAB
+                       }
+#endif // EXPAIRSEQ_USE_HASHTAB
+                       return;
+               } else {
+#if EXPAIRSEQ_USE_HASHTAB
+                       unsigned totalsize = ex_to<expairseq>(lh).seq.size()+1;
+                       if (calc_hashtabsize(totalsize)!=0) {
+                               construct_from_2_ex_via_exvector(lh, rh);
+                       } else {
+#endif // EXPAIRSEQ_USE_HASHTAB
+                               construct_from_expairseq_ex(ex_to<expairseq>(lh), rh);
+#if EXPAIRSEQ_USE_HASHTAB
+                       }
+#endif // EXPAIRSEQ_USE_HASHTAB
+                       return;
+               }
+       } else if (typeid(ex_to<basic>(rh)) == typeid(*this)) {
+#if EXPAIRSEQ_USE_HASHTAB
+               unsigned totalsize=ex_to<expairseq>(rh).seq.size()+1;
+               if (calc_hashtabsize(totalsize)!=0) {
+                       construct_from_2_ex_via_exvector(lh,rh);
+               } else {
+#endif // EXPAIRSEQ_USE_HASHTAB
+                       construct_from_expairseq_ex(ex_to<expairseq>(rh),lh);
+#if EXPAIRSEQ_USE_HASHTAB
+               }
+#endif // EXPAIRSEQ_USE_HASHTAB
+               return;
+       }
+       
+#if EXPAIRSEQ_USE_HASHTAB
+       if (calc_hashtabsize(2)!=0) {
+               construct_from_2_ex_via_exvector(lh,rh);
+               return;
+       }
+       hashtabsize = 0;
+#endif // EXPAIRSEQ_USE_HASHTAB
+       
+       if (is_exactly_a<numeric>(lh)) {
+               if (is_exactly_a<numeric>(rh)) {
+                       combine_overall_coeff(lh);
+                       combine_overall_coeff(rh);
+               } else {
+                       combine_overall_coeff(lh);
+                       seq.push_back(split_ex_to_pair(rh));
+               }
+       } else {
+               if (is_exactly_a<numeric>(rh)) {
+                       combine_overall_coeff(rh);
+                       seq.push_back(split_ex_to_pair(lh));
+               } else {
+                       expair p1 = split_ex_to_pair(lh);
+                       expair p2 = split_ex_to_pair(rh);
+                       
+                       int cmpval = p1.rest.compare(p2.rest);
+                       if (cmpval==0) {
+                               p1.coeff = ex_to<numeric>(p1.coeff).add_dyn(ex_to<numeric>(p2.coeff));
+                               if (!ex_to<numeric>(p1.coeff).is_zero()) {
+                                       // no further processing is necessary, since this
+                                       // one element will usually be recombined in eval()
+                                       seq.push_back(p1);
+                               }
+                       } else {
+                               seq.reserve(2);
+                               if (cmpval<0) {
+                                       seq.push_back(p1);
+                                       seq.push_back(p2);
+                               } else {
+                                       seq.push_back(p2);
+                                       seq.push_back(p1);
+                               }
+                       }
+               }
+       }
+}
+
+void expairseq::construct_from_2_expairseq(const expairseq &s1,
+                                                                                  const expairseq &s2)
+{
+       combine_overall_coeff(s1.overall_coeff);
+       combine_overall_coeff(s2.overall_coeff);
+
+       epvector::const_iterator first1 = s1.seq.begin();
+       epvector::const_iterator last1 = s1.seq.end();
+       epvector::const_iterator first2 = s2.seq.begin();
+       epvector::const_iterator last2 = s2.seq.end();
+
+       seq.reserve(s1.seq.size()+s2.seq.size());
+
+       bool needs_further_processing=false;
+       
+       while (first1!=last1 && first2!=last2) {
+               int cmpval = (*first1).rest.compare((*first2).rest);
+
+               if (cmpval==0) {
+                       // combine terms
+                       const numeric &newcoeff = ex_to<numeric>(first1->coeff).
+                                                  add(ex_to<numeric>(first2->coeff));
+                       if (!newcoeff.is_zero()) {
+                               seq.push_back(expair(first1->rest,newcoeff));
+                               if (expair_needs_further_processing(seq.end()-1)) {
+                                       needs_further_processing = true;
+                               }
+                       }
+                       ++first1;
+                       ++first2;
+               } else if (cmpval<0) {
+                       seq.push_back(*first1);
+                       ++first1;
+               } else {
+                       seq.push_back(*first2);
+                       ++first2;
+               }
+       }
+       
+       while (first1!=last1) {
+               seq.push_back(*first1);
+               ++first1;
+       }
+       while (first2!=last2) {
+               seq.push_back(*first2);
+               ++first2;
+       }
+       
+       if (needs_further_processing) {
+               epvector v = seq;
+               seq.clear();
+               construct_from_epvector(v);
+       }
+}
+
+void expairseq::construct_from_expairseq_ex(const expairseq &s,
+                                                                                       const ex &e)
+{
+       combine_overall_coeff(s.overall_coeff);
+       if (is_exactly_a<numeric>(e)) {
+               combine_overall_coeff(e);
+               seq = s.seq;
+               return;
+       }
+       
+       epvector::const_iterator first = s.seq.begin();
+       epvector::const_iterator last = s.seq.end();
+       expair p = split_ex_to_pair(e);
+       
+       seq.reserve(s.seq.size()+1);
+       bool p_pushed = false;
+       
+       bool needs_further_processing=false;
+       
+       // merge p into s.seq
+       while (first!=last) {
+               int cmpval = (*first).rest.compare(p.rest);
+               if (cmpval==0) {
+                       // combine terms
+                       const numeric &newcoeff = ex_to<numeric>(first->coeff).
+                                                  add(ex_to<numeric>(p.coeff));
+                       if (!newcoeff.is_zero()) {
+                               seq.push_back(expair(first->rest,newcoeff));
+                               if (expair_needs_further_processing(seq.end()-1))
+                                       needs_further_processing = true;
+                       }
+                       ++first;
+                       p_pushed = true;
+                       break;
+               } else if (cmpval<0) {
+                       seq.push_back(*first);
+                       ++first;
+               } else {
+                       seq.push_back(p);
+                       p_pushed = true;
+                       break;
+               }
+       }
+       
+       if (p_pushed) {
+               // while loop exited because p was pushed, now push rest of s.seq
+               while (first!=last) {
+                       seq.push_back(*first);
+                       ++first;
+               }
+       } else {
+               // while loop exited because s.seq was pushed, now push p
+               seq.push_back(p);
+       }
+
+       if (needs_further_processing) {
+               epvector v = seq;
+               seq.clear();
+               construct_from_epvector(v);
+       }
+}
+
+void expairseq::construct_from_exvector(const exvector &v)
+{
+       // simplifications: +(a,+(b,c),d) -> +(a,b,c,d) (associativity)
+       //                  +(d,b,c,a) -> +(a,b,c,d) (canonicalization)
+       //                  +(...,x,*(x,c1),*(x,c2)) -> +(...,*(x,1+c1+c2)) (c1, c2 numeric())
+       //                  (same for (+,*) -> (*,^)
+
+       make_flat(v);
+#if EXPAIRSEQ_USE_HASHTAB
+       combine_same_terms();
+#else
+       canonicalize();
+       combine_same_terms_sorted_seq();
+#endif // EXPAIRSEQ_USE_HASHTAB
 }
 
-void expairseq::combine_same_terms_sorted_seq(void)
+void expairseq::construct_from_epvector(const epvector &v, bool do_index_renaming)
 {
-    bool needs_further_processing=false;
-    
-    // combine same terms, drop term with coeff 0
-    if (seq.size()>1) {
-        epvector::iterator itin1=seq.begin();
-        epvector::iterator itin2=itin1+1;
-        epvector::iterator itout=itin1;
-        epvector::iterator last=seq.end();
-        // must_copy will be set to true the first time some combination is possible
-        // from then on the sequence has changed and must be compacted
-        bool must_copy=false;
-        while (itin2!=last) {
-            if ((*itin1).rest.compare((*itin2).rest)==0) {
-                (*itin1).coeff=ex_to_numeric((*itin1).coeff).
-                               add_dyn(ex_to_numeric((*itin2).coeff));
-                if (expair_needs_further_processing(itin1)) {
-                    needs_further_processing = true;
-                }
-                must_copy=true;
-            } else {
-                if (!ex_to_numeric((*itin1).coeff).is_zero()) {
-                    if (must_copy) {
-                        *itout=*itin1;
-                    }
-                    ++itout;
-                }
-                itin1=itin2;
-            }
-            ++itin2;
-        }
-        if (!ex_to_numeric((*itin1).coeff).is_zero()) {
-            if (must_copy) {
-                *itout=*itin1;
-            }
-            ++itout;
-        }
-        if (itout!=last) {
-            seq.erase(itout,last);
-        }
-    }
-
-    /*
-    cout << "after combine" << endl;
-    for (epvector::const_iterator cit=seq.begin(); cit!=seq.end(); ++cit) {
-        (*cit).printraw(cout);
-    }
-    cout << endl;
-    cout.flush();
-    */
-    
-    if (needs_further_processing) {
-        epvector v=seq;
-        seq.clear();
-        construct_from_epvector(v);
-    }
-}
+       // simplifications: +(a,+(b,c),d) -> +(a,b,c,d) (associativity)
+       //                  +(d,b,c,a) -> +(a,b,c,d) (canonicalization)
+       //                  +(...,x,*(x,c1),*(x,c2)) -> +(...,*(x,1+c1+c2)) (c1, c2 numeric())
+       //                  (same for (+,*) -> (*,^)
 
-#ifdef EXPAIRSEQ_USE_HASHTAB
+       make_flat(v, do_index_renaming);
+#if EXPAIRSEQ_USE_HASHTAB
+       combine_same_terms();
+#else
+       canonicalize();
+       combine_same_terms_sorted_seq();
+#endif // EXPAIRSEQ_USE_HASHTAB
+}
+
+/** Combine this expairseq with argument exvector.
+ *  It cares for associativity as well as for special handling of numerics. */
+void expairseq::make_flat(const exvector &v)
+{
+       exvector::const_iterator cit;
+       
+       // count number of operands which are of same expairseq derived type
+       // and their cumulative number of operands
+       int nexpairseqs = 0;
+       int noperands = 0;
+       bool do_idx_rename = false;
+       
+       cit = v.begin();
+       while (cit!=v.end()) {
+               if (typeid(ex_to<basic>(*cit)) == typeid(*this)) {
+                       ++nexpairseqs;
+                       noperands += ex_to<expairseq>(*cit).seq.size();
+               }
+               if (is_a<mul>(*this) && (!do_idx_rename) &&
+                               cit->info(info_flags::has_indices))
+                       do_idx_rename = true;
+               ++cit;
+       }
+       
+       // reserve seq and coeffseq which will hold all operands
+       seq.reserve(v.size()+noperands-nexpairseqs);
+       
+       // copy elements and split off numerical part
+       make_flat_inserter mf(v, do_idx_rename);
+       cit = v.begin();
+       while (cit!=v.end()) {
+               if (typeid(ex_to<basic>(*cit)) == typeid(*this)) {
+                       ex newfactor = mf.handle_factor(*cit, _ex1);
+                       const expairseq &subseqref = ex_to<expairseq>(newfactor);
+                       combine_overall_coeff(subseqref.overall_coeff);
+                       epvector::const_iterator cit_s = subseqref.seq.begin();
+                       while (cit_s!=subseqref.seq.end()) {
+                               seq.push_back(*cit_s);
+                               ++cit_s;
+                       }
+               } else {
+                       if (is_exactly_a<numeric>(*cit))
+                               combine_overall_coeff(*cit);
+                       else {
+                               ex newfactor = mf.handle_factor(*cit, _ex1);
+                               seq.push_back(split_ex_to_pair(newfactor));
+                       }
+               }
+               ++cit;
+       }
+}
+
+/** Combine this expairseq with argument epvector.
+ *  It cares for associativity as well as for special handling of numerics. */
+void expairseq::make_flat(const epvector &v, bool do_index_renaming)
+{
+       epvector::const_iterator cit;
+       
+       // count number of operands which are of same expairseq derived type
+       // and their cumulative number of operands
+       int nexpairseqs = 0;
+       int noperands = 0;
+       bool really_need_rename_inds = false;
+       
+       cit = v.begin();
+       while (cit!=v.end()) {
+               if (typeid(ex_to<basic>(cit->rest)) == typeid(*this)) {
+                       ++nexpairseqs;
+                       noperands += ex_to<expairseq>(cit->rest).seq.size();
+               }
+               if ((!really_need_rename_inds) && is_a<mul>(*this) &&
+                               cit->rest.info(info_flags::has_indices))
+                       really_need_rename_inds = true;
+               ++cit;
+       }
+       do_index_renaming = do_index_renaming && really_need_rename_inds;
+       
+       // reserve seq and coeffseq which will hold all operands
+       seq.reserve(v.size()+noperands-nexpairseqs);
+       make_flat_inserter mf(v, do_index_renaming);
+       
+       // copy elements and split off numerical part
+       cit = v.begin();
+       while (cit!=v.end()) {
+               if ((typeid(ex_to<basic>(cit->rest)) == typeid(*this)) &&
+                   this->can_make_flat(*cit)) {
+                       ex newrest = mf.handle_factor(cit->rest, cit->coeff);
+                       const expairseq &subseqref = ex_to<expairseq>(newrest);
+                       combine_overall_coeff(ex_to<numeric>(subseqref.overall_coeff),
+                                                           ex_to<numeric>(cit->coeff));
+                       epvector::const_iterator cit_s = subseqref.seq.begin();
+                       while (cit_s!=subseqref.seq.end()) {
+                               seq.push_back(expair(cit_s->rest,
+                                                    ex_to<numeric>(cit_s->coeff).mul_dyn(ex_to<numeric>(cit->coeff))));
+                               //seq.push_back(combine_pair_with_coeff_to_pair(*cit_s,
+                               //                                              (*cit).coeff));
+                               ++cit_s;
+                       }
+               } else {
+                       if (cit->is_canonical_numeric())
+                               combine_overall_coeff(mf.handle_factor(cit->rest, _ex1));
+                       else {
+                               ex rest = cit->rest;
+                               ex newrest = mf.handle_factor(rest, cit->coeff);
+                               if (are_ex_trivially_equal(newrest, rest))
+                                       seq.push_back(*cit);
+                               else
+                                       seq.push_back(expair(newrest, cit->coeff));
+                       }
+               }
+               ++cit;
+       }
+}
+
+/** Brings this expairseq into a sorted (canonical) form. */
+void expairseq::canonicalize()
+{
+       std::sort(seq.begin(), seq.end(), expair_rest_is_less());
+}
+
+
+/** Compact a presorted expairseq by combining all matching expairs to one
+ *  each.  On an add object, this is responsible for 2*x+3*x+y -> 5*x+y, for
+ *  instance. */
+void expairseq::combine_same_terms_sorted_seq()
+{
+       if (seq.size()<2)
+               return;
+
+       bool needs_further_processing = false;
+
+       epvector::iterator itin1 = seq.begin();
+       epvector::iterator itin2 = itin1+1;
+       epvector::iterator itout = itin1;
+       epvector::iterator last = seq.end();
+       // must_copy will be set to true the first time some combination is 
+       // possible from then on the sequence has changed and must be compacted
+       bool must_copy = false;
+       while (itin2!=last) {
+               if (itin1->rest.compare(itin2->rest)==0) {
+                       itin1->coeff = ex_to<numeric>(itin1->coeff).
+                                      add_dyn(ex_to<numeric>(itin2->coeff));
+                       if (expair_needs_further_processing(itin1))
+                               needs_further_processing = true;
+                       must_copy = true;
+               } else {
+                       if (!ex_to<numeric>(itin1->coeff).is_zero()) {
+                               if (must_copy)
+                                       *itout = *itin1;
+                               ++itout;
+                       }
+                       itin1 = itin2;
+               }
+               ++itin2;
+       }
+       if (!ex_to<numeric>(itin1->coeff).is_zero()) {
+               if (must_copy)
+                       *itout = *itin1;
+               ++itout;
+       }
+       if (itout!=last)
+               seq.erase(itout,last);
+
+       if (needs_further_processing) {
+               epvector v = seq;
+               seq.clear();
+               construct_from_epvector(v);
+       }
+}
+
+#if EXPAIRSEQ_USE_HASHTAB
 
 unsigned expairseq::calc_hashtabsize(unsigned sz) const
 {
-    unsigned size;
-    unsigned nearest_power_of_2 = 1 << log2(sz);
-    //    if (nearest_power_of_2 < maxhashtabsize/hashtabfactor) {
-    //  size=nearest_power_of_2*hashtabfactor;
-    size=nearest_power_of_2/hashtabfactor;
-    if (size<minhashtabsize) return 0;
-    ASSERT(hashtabsize<=0x8000000U); // really max size due to 31 bit hashing
-    // hashtabsize must be a power of 2
-    ASSERT((1U << log2(size))==size);
-    return size;
-}
-
-unsigned expairseq::calc_hashindex(ex const & e) const
-{
-    // calculate hashindex
-    unsigned hash=e.gethash();
-    unsigned hashindex;
-    if (is_a_numeric_hash(hash)) {
-        hashindex=hashmask;
-    } else {
-        hashindex=hash & hashmask;
-        // last hashtab entry is reserved for numerics
-        if (hashindex==hashmask) hashindex=0;
-    }
-    ASSERT(hashindex>=0);
-    ASSERT((hashindex<hashtabsize)||(hashtabsize==0));
-    return hashindex;
-}
-
-void expairseq::shrink_hashtab(void)
-{
-    unsigned new_hashtabsize;
-    while (hashtabsize!=(new_hashtabsize=calc_hashtabsize(seq.size()))) {
-        ASSERT(new_hashtabsize<hashtabsize);
-        if (new_hashtabsize==0) {
-            hashtab.clear();
-            hashtabsize=0;
-            canonicalize();
-            return;
-        }
-        
-        // shrink by a factor of 2
-        unsigned half_hashtabsize=hashtabsize/2;
-        for (unsigned i=0; i<half_hashtabsize-1; ++i) {
-            hashtab[i].merge(hashtab[i+half_hashtabsize],epp_is_less());
-        }
-        // special treatment for numeric hashes
-        hashtab[0].merge(hashtab[half_hashtabsize-1],epp_is_less());
-        hashtab[half_hashtabsize-1]=hashtab[hashtabsize-1];
-        hashtab.resize(half_hashtabsize);
-        hashtabsize=half_hashtabsize;
-        hashmask=hashtabsize-1;
-    }
+       unsigned size;
+       unsigned nearest_power_of_2 = 1 << log2(sz);
+       // if (nearest_power_of_2 < maxhashtabsize/hashtabfactor) {
+       //  size = nearest_power_of_2*hashtabfactor;
+       size = nearest_power_of_2/hashtabfactor;
+       if (size<minhashtabsize)
+               return 0;
+
+       // hashtabsize must be a power of 2
+       GINAC_ASSERT((1U << log2(size))==size);
+       return size;
+}
+
+unsigned expairseq::calc_hashindex(const ex &e) const
+{
+       // calculate hashindex
+       unsigned hashindex;
+       if (is_a<numeric>(e)) {
+               hashindex = hashmask;
+       } else {
+               hashindex = e.gethash() & hashmask;
+               // last hashtab entry is reserved for numerics
+               if (hashindex==hashmask) hashindex = 0;
+       }
+       GINAC_ASSERT((hashindex<hashtabsize)||(hashtabsize==0));
+       return hashindex;
+}
+
+void expairseq::shrink_hashtab()
+{
+       unsigned new_hashtabsize;
+       while (hashtabsize!=(new_hashtabsize=calc_hashtabsize(seq.size()))) {
+               GINAC_ASSERT(new_hashtabsize<hashtabsize);
+               if (new_hashtabsize==0) {
+                       hashtab.clear();
+                       hashtabsize = 0;
+                       canonicalize();
+                       return;
+               }
+               
+               // shrink by a factor of 2
+               unsigned half_hashtabsize = hashtabsize/2;
+               for (unsigned i=0; i<half_hashtabsize-1; ++i)
+                       hashtab[i].merge(hashtab[i+half_hashtabsize],epp_is_less());
+               // special treatment for numeric hashes
+               hashtab[0].merge(hashtab[half_hashtabsize-1],epp_is_less());
+               hashtab[half_hashtabsize-1] = hashtab[hashtabsize-1];
+               hashtab.resize(half_hashtabsize);
+               hashtabsize = half_hashtabsize;
+               hashmask = hashtabsize-1;
+       }
 }
 
 void expairseq::remove_hashtab_entry(epvector::const_iterator element)
 {
-    if (hashtabsize==0) return; // nothing to do
-    
-    // calculate hashindex of element to be deleted
-    unsigned hashindex=calc_hashindex((*element).rest);
-
-    // find it in hashtab and remove it
-    epplist & eppl=hashtab[hashindex];
-    epplist::iterator epplit=eppl.begin();
-    bool erased=false;
-    while (epplit!=eppl.end()) {
-        if (*epplit == element) {
-            eppl.erase(epplit);
-            erased=true;
-            break;
-        }
-        ++epplit;
-    }
-    if (!erased) {
-        printtree(cout,0);
-        cout << "tried to erase " << element-seq.begin() << endl;
-        cout << "size " << seq.end()-seq.begin() << endl;
-
-        unsigned hashindex=calc_hashindex((*element).rest);
-        epplist & eppl=hashtab[hashindex];
-        epplist::iterator epplit=eppl.begin();
-        bool erased=false;
-        while (epplit!=eppl.end()) {
-            if (*epplit == element) {
-                eppl.erase(epplit);
-                erased=true;
-                break;
-            }
-            ++epplit;
-        }
-        ASSERT(erased);
-    }
-    ASSERT(erased);
+       if (hashtabsize==0)
+               return; // nothing to do
+       
+       // calculate hashindex of element to be deleted
+       unsigned hashindex = calc_hashindex((*element).rest);
+
+       // find it in hashtab and remove it
+       epplist &eppl = hashtab[hashindex];
+       epplist::iterator epplit = eppl.begin();
+       bool erased = false;
+       while (epplit!=eppl.end()) {
+               if (*epplit == element) {
+                       eppl.erase(epplit);
+                       erased = true;
+                       break;
+               }
+               ++epplit;
+       }
+       if (!erased) {
+               std::cout << "tried to erase " << element-seq.begin() << std::endl;
+               std::cout << "size " << seq.end()-seq.begin() << std::endl;
+
+               unsigned hashindex = calc_hashindex(element->rest);
+               epplist &eppl = hashtab[hashindex];
+               epplist::iterator epplit = eppl.begin();
+               bool erased = false;
+               while (epplit!=eppl.end()) {
+                       if (*epplit == element) {
+                               eppl.erase(epplit);
+                               erased = true;
+                               break;
+                       }
+                       ++epplit;
+               }
+               GINAC_ASSERT(erased);
+       }
+       GINAC_ASSERT(erased);
 }
 
 void expairseq::move_hashtab_entry(epvector::const_iterator oldpos,
                                    epvector::iterator newpos)
 {
-    ASSERT(hashtabsize!=0);
-    
-    // calculate hashindex of element which was moved
-    unsigned hashindex=calc_hashindex((*newpos).rest);
-
-    // find it in hashtab and modify it
-    epplist & eppl=hashtab[hashindex];
-    epplist::iterator epplit=eppl.begin();
-    while (epplit!=eppl.end()) {
-        if (*epplit == oldpos) {
-            *epplit=newpos;
-            break;
-        }
-        ++epplit;
-    }
-    ASSERT(epplit!=eppl.end());
-}
-
-void expairseq::sorted_insert(epplist & eppl, epp elem)
-{
-    epplist::iterator current=eppl.begin();
-    while ((current!=eppl.end())&&((*(*current)).is_less(*elem))) {
-        ++current;
-    }
-    eppl.insert(current,elem);
+       GINAC_ASSERT(hashtabsize!=0);
+       
+       // calculate hashindex of element which was moved
+       unsigned hashindex=calc_hashindex((*newpos).rest);
+
+       // find it in hashtab and modify it
+       epplist &eppl = hashtab[hashindex];
+       epplist::iterator epplit = eppl.begin();
+       while (epplit!=eppl.end()) {
+               if (*epplit == oldpos) {
+                       *epplit = newpos;
+                       break;
+               }
+               ++epplit;
+       }
+       GINAC_ASSERT(epplit!=eppl.end());
+}
+
+void expairseq::sorted_insert(epplist &eppl, epvector::const_iterator elem)
+{
+       epplist::const_iterator current = eppl.begin();
+       while ((current!=eppl.end()) && ((*current)->is_less(*elem))) {
+               ++current;
+       }
+       eppl.insert(current,elem);
 }    
 
-void expairseq::build_hashtab_and_combine(epvector::iterator & first_numeric,
-                                          epvector::iterator & last_non_zero,
-                                          vector<bool> & touched,
-                                          unsigned & number_of_zeroes)
-{
-    epp current=seq.begin();
-
-    while (current!=first_numeric) {
-        if (is_ex_exactly_of_type((*current).rest,numeric)) {
-            --first_numeric;
-            iter_swap(current,first_numeric);
-        } else {
-            // calculate hashindex
-            unsigned currenthashindex=calc_hashindex((*current).rest);
-
-            // test if there is already a matching expair in the hashtab-list
-            epplist & eppl=hashtab[currenthashindex];
-            epplist::iterator epplit=eppl.begin();
-            while (epplit!=eppl.end()) {
-                if ((*current).rest.is_equal((*(*epplit)).rest)) break;
-                ++epplit;
-            }
-            if (epplit==eppl.end()) {
-                // no matching expair found, append this to end of list
-                sorted_insert(eppl,current);
-                ++current;
-            } else {
-                // epplit points to a matching expair, combine it with current
-                (*(*epplit)).coeff=ex_to_numeric((*(*epplit)).coeff).
-                                   add_dyn(ex_to_numeric((*current).coeff));
-                
-                // move obsolete current expair to end by swapping with last_non_zero element
-                // if this was a numeric, it is swapped with the expair before first_numeric 
-                iter_swap(current,last_non_zero);
-                --first_numeric;
-                if (first_numeric!=last_non_zero) iter_swap(first_numeric,current);
-                --last_non_zero;
-                ++number_of_zeroes;
-                // test if combined term has coeff 0 and can be removed is done later
-                touched[(*epplit)-seq.begin()]=true;
-            }
-        }
-    }
-}    
-
-void expairseq::drop_coeff_0_terms(epvector::iterator & first_numeric,
-                                   epvector::iterator & last_non_zero,
-                                   vector<bool> & touched,
-                                   unsigned & number_of_zeroes)
-{
-    // move terms with coeff 0 to end and remove them from hashtab
-    // check only those elements which have been touched
-    epp current=seq.begin();
-    unsigned i=0;
-    while (current!=first_numeric) {
-        if (!touched[i]) {
-            ++current;
-            ++i;
-        } else if (!ex_to_numeric((*current).coeff).is_equal(numZERO())) {
-            ++current;
-            ++i;
-        } else {
-            remove_hashtab_entry(current);
-
-            // move element to the end, unless it is already at the end
-            if (current!=last_non_zero) {
-                iter_swap(current,last_non_zero);
-                --first_numeric;
-                bool numeric_swapped=first_numeric!=last_non_zero;
-                if (numeric_swapped) iter_swap(first_numeric,current);
-                epvector::iterator changed_entry;
-
-                if (numeric_swapped) {
-                    changed_entry=first_numeric;
-                } else {
-                    changed_entry=last_non_zero;
-                }
-
-                --last_non_zero;
-                ++number_of_zeroes;
-
-                if (first_numeric!=current) {
-                
-                    // change entry in hashtab which referred to first_numeric or last_non_zero to current
-                    move_hashtab_entry(changed_entry,current);
-                    touched[current-seq.begin()]=touched[changed_entry-seq.begin()];
-                }
-            } else {
-                --first_numeric;
-                --last_non_zero;
-                ++number_of_zeroes;
-            }
-        }
-    }
-    ASSERT(i==current-seq.begin());
-}
-
-bool expairseq::has_coeff_0(void) const
-{
-    for (epvector::const_iterator cit=seq.begin(); cit!=seq.end(); ++cit) {
-        if ((*cit).coeff.is_equal(exZERO())) {
-            return true;
-        }
-    }
-    return false;
+void expairseq::build_hashtab_and_combine(epvector::iterator &first_numeric,
+                                          epvector::iterator &last_non_zero,
+                                          std::vector<bool> &touched,
+                                          unsigned &number_of_zeroes)
+{
+       epp current = seq.begin();
+
+       while (current!=first_numeric) {
+               if (is_exactly_a<numeric>(current->rest)) {
+                       --first_numeric;
+                       iter_swap(current,first_numeric);
+               } else {
+                       // calculate hashindex
+                       unsigned currenthashindex = calc_hashindex(current->rest);
+
+                       // test if there is already a matching expair in the hashtab-list
+                       epplist &eppl=hashtab[currenthashindex];
+                       epplist::iterator epplit = eppl.begin();
+                       while (epplit!=eppl.end()) {
+                               if (current->rest.is_equal((*epplit)->rest))
+                                       break;
+                               ++epplit;
+                       }
+                       if (epplit==eppl.end()) {
+                               // no matching expair found, append this to end of list
+                               sorted_insert(eppl,current);
+                               ++current;
+                       } else {
+                               // epplit points to a matching expair, combine it with current
+                               (*epplit)->coeff = ex_to<numeric>((*epplit)->coeff).
+                                                  add_dyn(ex_to<numeric>(current->coeff));
+                               
+                               // move obsolete current expair to end by swapping with last_non_zero element
+                               // if this was a numeric, it is swapped with the expair before first_numeric 
+                               iter_swap(current,last_non_zero);
+                               --first_numeric;
+                               if (first_numeric!=last_non_zero) iter_swap(first_numeric,current);
+                               --last_non_zero;
+                               ++number_of_zeroes;
+                               // test if combined term has coeff 0 and can be removed is done later
+                               touched[(*epplit)-seq.begin()] = true;
+                       }
+               }
+       }
+}
+
+void expairseq::drop_coeff_0_terms(epvector::iterator &first_numeric,
+                                   epvector::iterator &last_non_zero,
+                                   std::vector<bool> &touched,
+                                   unsigned &number_of_zeroes)
+{
+       // move terms with coeff 0 to end and remove them from hashtab
+       // check only those elements which have been touched
+       epp current = seq.begin();
+       size_t i = 0;
+       while (current!=first_numeric) {
+               if (!touched[i]) {
+                       ++current;
+                       ++i;
+               } else if (!ex_to<numeric>((*current).coeff).is_zero()) {
+                       ++current;
+                       ++i;
+               } else {
+                       remove_hashtab_entry(current);
+                       
+                       // move element to the end, unless it is already at the end
+                       if (current!=last_non_zero) {
+                               iter_swap(current,last_non_zero);
+                               --first_numeric;
+                               bool numeric_swapped = first_numeric!=last_non_zero;
+                               if (numeric_swapped)
+                                       iter_swap(first_numeric,current);
+                               epvector::iterator changed_entry;
+
+                               if (numeric_swapped)
+                                       changed_entry = first_numeric;
+                               else
+                                       changed_entry = last_non_zero;
+                               
+                               --last_non_zero;
+                               ++number_of_zeroes;
+
+                               if (first_numeric!=current) {
+
+                                       // change entry in hashtab which referred to first_numeric or last_non_zero to current
+                                       move_hashtab_entry(changed_entry,current);
+                                       touched[current-seq.begin()] = touched[changed_entry-seq.begin()];
+                               }
+                       } else {
+                               --first_numeric;
+                               --last_non_zero;
+                               ++number_of_zeroes;
+                       }
+               }
+       }
+       GINAC_ASSERT(i==current-seq.begin());
+}
+
+/** True if one of the coeffs vanishes, otherwise false.
+ *  This would be an invariant violation, so this should only be used for
+ *  debugging purposes. */
+bool expairseq::has_coeff_0() const
+{
+       epvector::const_iterator i = seq.begin(), end = seq.end();
+       while (i != end) {
+               if (i->coeff.is_zero())
+                       return true;
+               ++i;
+       }
+       return false;
 }
 
 void expairseq::add_numerics_to_hashtab(epvector::iterator first_numeric,
-                                        epvector::const_iterator last_non_zero)
-{
-    if (first_numeric==seq.end()) return; // no numerics    
-
-    epvector::iterator current=first_numeric;
-    epvector::const_iterator last=last_non_zero+1;
-    while (current!=last) {
-        sorted_insert(hashtab[hashmask],current);
-        ++current;
-    }
-}
-
-void expairseq::combine_same_terms(void)
-{
-    // combine same terms, drop term with coeff 0, move numerics to end
-    
-    // calculate size of hashtab
-    hashtabsize=calc_hashtabsize(seq.size());
-
-    // hashtabsize is a power of 2
-    hashmask=hashtabsize-1;
-
-    // allocate hashtab
-    hashtab.clear();
-    hashtab.resize(hashtabsize);
-
-    if (hashtabsize==0) {
-        canonicalize();
-        combine_same_terms_sorted_seq();
-        ASSERT(!has_coeff_0());
-        return;
-    }
-
-    // iterate through seq, move numerics to end,
-    // fill hashtab and combine same terms
-    epvector::iterator first_numeric=seq.end();
-    epvector::iterator last_non_zero=seq.end()-1;
-
-    vector<bool> touched;
-    touched.reserve(seq.size());
-    for (unsigned i=0; i<seq.size(); ++i) touched[i]=false;
-
-    unsigned number_of_zeroes=0;
-
-    ASSERT(!has_coeff_0());
-    build_hashtab_and_combine(first_numeric,last_non_zero,touched,number_of_zeroes);
-    /*
-    cout << "in combine:" << endl;
-    printtree(cout,0);
-    cout << "size=" << seq.end() - seq.begin() << endl;
-    cout << "first_numeric=" << first_numeric - seq.begin() << endl;
-    cout << "last_non_zero=" << last_non_zero - seq.begin() << endl;
-    for (unsigned i=0; i<seq.size(); ++i) {
-        if (touched[i]) cout << i << " is touched" << endl;
-    }
-    cout << "end in combine" << endl;
-    */
-    
-    // there should not be any terms with coeff 0 from the beginning,
-    // so it should be safe to skip this step
-    if (number_of_zeroes!=0) {
-        drop_coeff_0_terms(first_numeric,last_non_zero,touched,number_of_zeroes);
-        /*
-        cout << "in combine after drop:" << endl;
-        printtree(cout,0);
-        cout << "size=" << seq.end() - seq.begin() << endl;
-        cout << "first_numeric=" << first_numeric - seq.begin() << endl;
-        cout << "last_non_zero=" << last_non_zero - seq.begin() << endl;
-        for (unsigned i=0; i<seq.size(); ++i) {
-            if (touched[i]) cout << i << " is touched" << endl;
-        }
-        cout << "end in combine after drop" << endl;
-        */
-    }
-
-    add_numerics_to_hashtab(first_numeric,last_non_zero);
-
-    // pop zero elements
-    for (unsigned i=0; i<number_of_zeroes; ++i) {
-        seq.pop_back();
-    }
-
-    // shrink hashtabsize to calculated value
-    ASSERT(!has_coeff_0());
-
-    shrink_hashtab();
-
-    ASSERT(!has_coeff_0());
-}
-
-#endif // def EXPAIRSEQ_USE_HASHTAB
-
+                                                                               epvector::const_iterator last_non_zero)
+{
+       if (first_numeric == seq.end()) return; // no numerics
+       
+       epvector::const_iterator current = first_numeric, last = last_non_zero + 1;
+       while (current != last) {
+               sorted_insert(hashtab[hashmask], current);
+               ++current;
+       }
+}
+
+void expairseq::combine_same_terms()
+{
+       // combine same terms, drop term with coeff 0, move numerics to end
+       
+       // calculate size of hashtab
+       hashtabsize = calc_hashtabsize(seq.size());
+       
+       // hashtabsize is a power of 2
+       hashmask = hashtabsize-1;
+       
+       // allocate hashtab
+       hashtab.clear();
+       hashtab.resize(hashtabsize);
+       
+       if (hashtabsize==0) {
+               canonicalize();
+               combine_same_terms_sorted_seq();
+               GINAC_ASSERT(!has_coeff_0());
+               return;
+       }
+       
+       // iterate through seq, move numerics to end,
+       // fill hashtab and combine same terms
+       epvector::iterator first_numeric = seq.end();
+       epvector::iterator last_non_zero = seq.end()-1;
+       
+       size_t num = seq.size();
+       std::vector<bool> touched(num);
+       
+       unsigned number_of_zeroes = 0;
+       
+       GINAC_ASSERT(!has_coeff_0());
+       build_hashtab_and_combine(first_numeric,last_non_zero,touched,number_of_zeroes);
+       
+       // there should not be any terms with coeff 0 from the beginning,
+       // so it should be safe to skip this step
+       if (number_of_zeroes!=0) {
+               drop_coeff_0_terms(first_numeric,last_non_zero,touched,number_of_zeroes);
+       }
+       
+       add_numerics_to_hashtab(first_numeric,last_non_zero);
+       
+       // pop zero elements
+       for (unsigned i=0; i<number_of_zeroes; ++i) {
+               seq.pop_back();
+       }
+       
+       // shrink hashtabsize to calculated value
+       GINAC_ASSERT(!has_coeff_0());
+       
+       shrink_hashtab();
+       
+       GINAC_ASSERT(!has_coeff_0());
+}
+
+#endif // EXPAIRSEQ_USE_HASHTAB
+
+/** Check if this expairseq is in sorted (canonical) form.  Useful mainly for
+ *  debugging or in assertions since being sorted is an invariance. */
 bool expairseq::is_canonical() const
 {
-    if (seq.size()<=1) return 1;
-
-#ifdef EXPAIRSEQ_USE_HASHTAB
-    if (hashtabsize>0) return 1; // not canoncalized
-#endif // def EXPAIRSEQ_USE_HASHTAB
-    
-    epvector::const_iterator it=seq.begin();
-    epvector::const_iterator it_last=it;
-    for (++it; it!=seq.end(); it_last=it, ++it) {
-        if (!((*it_last).is_less(*it)||(*it_last).is_equal(*it))) {
-            if (!is_ex_exactly_of_type((*it_last).rest,numeric)||
-                !is_ex_exactly_of_type((*it).rest,numeric)) {
-                // double test makes it easier to set a breakpoint...
-                if (!is_ex_exactly_of_type((*it_last).rest,numeric)||
-                    !is_ex_exactly_of_type((*it).rest,numeric)) {
-                    printpair(cout,*it_last,0);
-                    cout << ">";
-                    printpair(cout,*it,0);
-                    cout << "\n";
-                    cout << "pair1:" << endl;
-                    (*it_last).rest.printtree(cout);
-                    (*it_last).coeff.printtree(cout);
-                    cout << "pair2:" << endl;
-                    (*it).rest.printtree(cout);
-                    (*it).coeff.printtree(cout);
-                    return 0;
-                }
-            }
-        }
-    }
-    return 1;
-}
-
-epvector * expairseq::expandchildren(unsigned options) const
-{
-    epvector::const_iterator last=seq.end();
-    epvector::const_iterator cit=seq.begin();
-    while (cit!=last) {
-        ex const & expanded_ex=(*cit).rest.expand(options);
-        if (!are_ex_trivially_equal((*cit).rest,expanded_ex)) {
-
-            // something changed, copy seq, eval and return it
-            epvector *s=new epvector;
-            s->reserve(seq.size());
-
-            // copy parts of seq which are known not to have changed
-            epvector::const_iterator cit2=seq.begin();
-            while (cit2!=cit) {
-                s->push_back(*cit2);
-                ++cit2;
-            }
-            // copy first changed element
-            s->push_back(combine_ex_with_coeff_to_pair(expanded_ex,
-                                                       (*cit2).coeff));
-            ++cit2;
-            // copy rest
-            while (cit2!=last) {
-                s->push_back(combine_ex_with_coeff_to_pair((*cit2).rest.expand(options),
-                                                           (*cit2).coeff));
-                ++cit2;
-            }
-            return s;
-        }
-        ++cit;
-    }
-    
-    return 0; // nothing has changed
-}
-   
-epvector * expairseq::evalchildren(int level) const
-{
-    // returns a NULL pointer if nothing had to be evaluated
-    // returns a pointer to a newly created epvector otherwise
-    // (which has to be deleted somewhere else)
-
-    if (level==1) {
-        return 0;
-    }
-    if (level == -max_recursion_level) {
-        throw(std::runtime_error("max recursion level reached"));
-    }
-
-    --level;
-    epvector::const_iterator last=seq.end();
-    epvector::const_iterator cit=seq.begin();
-    while (cit!=last) {
-        ex const & evaled_ex=(*cit).rest.eval(level);
-        if (!are_ex_trivially_equal((*cit).rest,evaled_ex)) {
-
-           // something changed, copy seq, eval and return it
-            epvector *s=new epvector;
-            s->reserve(seq.size());
-
-            // copy parts of seq which are known not to have changed
-            epvector::const_iterator cit2=seq.begin();
-            while (cit2!=cit) {
-                s->push_back(*cit2);
-                ++cit2;
-            }
-            // copy first changed element
-            s->push_back(combine_ex_with_coeff_to_pair(evaled_ex,
-                                                       (*cit2).coeff));
-            ++cit2;
-            // copy rest
-            while (cit2!=last) {
-                s->push_back(combine_ex_with_coeff_to_pair((*cit2).rest.eval(level),
-                                                           (*cit2).coeff));
-                ++cit2;
-            }
-            return s;
-        }
-        ++cit;
-    }
-    
-    return 0; // nothing has changed
-}
-
-epvector expairseq::evalfchildren(int level) const
-{
-    epvector s;
-    s.reserve(seq.size());
-
-    if (level==1) {
-        return seq;
-    }
-    if (level == -max_recursion_level) {
-        throw(std::runtime_error("max recursion level reached"));
-    }
-    --level;
-    for (epvector::const_iterator it=seq.begin(); it!=seq.end(); ++it) {
-        s.push_back(combine_ex_with_coeff_to_pair((*it).rest.evalf(level),
-                                                  (*it).coeff));
-    }
-    return s;
-}
-
-epvector expairseq::normalchildren(int level) const
-{
-    epvector s;
-    s.reserve(seq.size());
-
-    if (level==1) {
-        return seq;
-    }
-    if (level == -max_recursion_level) {
-        throw(std::runtime_error("max recursion level reached"));
-    }
-    --level;
-    for (epvector::const_iterator it=seq.begin(); it!=seq.end(); ++it) {
-        s.push_back(combine_ex_with_coeff_to_pair((*it).rest.normal(level),
-                                                  (*it).coeff));
-    }
-    return s;
-}
-
-epvector expairseq::diffchildren(symbol const & y) const
-{
-    epvector s;
-    s.reserve(seq.size());
-
-    for (epvector::const_iterator it=seq.begin(); it!=seq.end(); ++it) {
-        s.push_back(combine_ex_with_coeff_to_pair((*it).rest.diff(y),
-                                                  (*it).coeff));
-    }
-    return s;
-}
-
-epvector * expairseq::subschildren(lst const & ls, lst const & lr) const
-{
-    // returns a NULL pointer if nothing had to be substituted
-    // returns a pointer to a newly created epvector otherwise
-    // (which has to be deleted somewhere else)
-
-    epvector::const_iterator last=seq.end();
-    epvector::const_iterator cit=seq.begin();
-    while (cit!=last) {
-        ex const & subsed_ex=(*cit).rest.subs(ls,lr);
-        if (!are_ex_trivially_equal((*cit).rest,subsed_ex)) {
-
-            // something changed, copy seq, subs and return it
-            epvector *s=new epvector;
-            s->reserve(seq.size());
-
-            // copy parts of seq which are known not to have changed
-            epvector::const_iterator cit2=seq.begin();
-            while (cit2!=cit) {
-                s->push_back(*cit2);
-                ++cit2;
-            }
-            // copy first changed element
-            s->push_back(combine_ex_with_coeff_to_pair(subsed_ex,
-                                                       (*cit2).coeff));
-            ++cit2;
-            // copy rest
-            while (cit2!=last) {
-                s->push_back(combine_ex_with_coeff_to_pair((*cit2).rest.subs(ls,lr),
-                                                           (*cit2).coeff));
-                ++cit2;
-           }
-            return s;
-        }
-        ++cit;
-    }
-    
-    return 0; // nothing has changed
-}
-
-/*
-epvector expairseq::subschildren(lst const & ls, lst const & lr) const
-{
-    epvector s;
-    s.reserve(seq.size());
-
-    for (epvector::const_iterator it=seq.begin(); it!=seq.end(); ++it) {
-        s.push_back(split_ex_to_pair((*it).rest.subs(ls,lr),(*it).coeff));
-    }
-    return s;
-}
-*/
-
-/*
-void expairseq::sort(epviter first, epviter last, expair_is_less comp)
-{
-    if (first != last) {
-        introsort_loop(first, last, lg(last - first) * 2, comp);
-        __final_insertion_sort(first, last, comp);
-    }
-}
-
-ptrdiff_t expairseq::lg(ptrdiff_t n)
-{
-    ptrdiff_t k;
-    for (k = 0; n > 1; n >>= 1) ++k;
-    return k;
-}
-
-void expairseq::introsort_loop(epviter first, epviter last,
-                               ptrdiff_t depth_limit, expair_is_less comp)
-{
-    while (last - first > stl_threshold) {
-        if (depth_limit == 0) {
-            partial_sort(first, last, last, comp);
-            return;
-        }
-        --depth_limit;
-        epviter cut = unguarded_partition(first, last,
-                      expair(__median(*first, *(first + (last - first)/2),
-                      *(last - 1), comp)), comp);
-        introsort_loop(cut, last, depth_limit, comp);
-        last = cut;
-    }
-}
-
-epviter expairseq::unguarded_partition(epviter first, epviter last, 
-                                       expair pivot, expair_is_less comp)
-{
-    while (1) {
-        while (comp(*first, pivot)) ++first;
-        --last;
-        while (comp(pivot, *last)) --last;
-        if (!(first < last)) return first;
-        iter_swap(first, last);
-        ++first;
-    }
-}
-
-void expairseq::partial_sort(epviter first, epviter middle, epviter last,
-                             expair_is_less comp) {
-  make_heap(first, middle, comp);
-  for (RandomAccessIterator i = middle; i < last; ++i)
-    if (comp(*i, *first))
-      __pop_heap(first, middle, i, T(*i), comp, distance_type(first));
-  sort_heap(first, middle, comp);
+       if (seq.size() <= 1)
+               return 1;
+       
+#if EXPAIRSEQ_USE_HASHTAB
+       if (hashtabsize > 0) return 1; // not canoncalized
+#endif // EXPAIRSEQ_USE_HASHTAB
+       
+       epvector::const_iterator it = seq.begin(), itend = seq.end();
+       epvector::const_iterator it_last = it;
+       for (++it; it!=itend; it_last=it, ++it) {
+               if (!(it_last->is_less(*it) || it_last->is_equal(*it))) {
+                       if (!is_exactly_a<numeric>(it_last->rest) ||
+                               !is_exactly_a<numeric>(it->rest)) {
+                               // double test makes it easier to set a breakpoint...
+                               if (!is_exactly_a<numeric>(it_last->rest) ||
+                                       !is_exactly_a<numeric>(it->rest)) {
+                                       printpair(std::clog, *it_last, 0);
+                                       std::clog << ">";
+                                       printpair(std::clog, *it, 0);
+                                       std::clog << "\n";
+                                       std::clog << "pair1:" << std::endl;
+                                       it_last->rest.print(print_tree(std::clog));
+                                       it_last->coeff.print(print_tree(std::clog));
+                                       std::clog << "pair2:" << std::endl;
+                                       it->rest.print(print_tree(std::clog));
+                                       it->coeff.print(print_tree(std::clog));
+                                       return 0;
+                               }
+                       }
+               }
+       }
+       return 1;
+}
+
+
+/** Member-wise expand the expairs in this sequence.
+ *
+ *  @see expairseq::expand()
+ *  @return pointer to epvector containing expanded pairs or zero pointer,
+ *  if no members were changed. */
+std::auto_ptr<epvector> expairseq::expandchildren(unsigned options) const
+{
+       const epvector::const_iterator last = seq.end();
+       epvector::const_iterator cit = seq.begin();
+       while (cit!=last) {
+               const ex &expanded_ex = cit->rest.expand(options);
+               if (!are_ex_trivially_equal(cit->rest,expanded_ex)) {
+                       
+                       // something changed, copy seq, eval and return it
+                       std::auto_ptr<epvector> s(new epvector);
+                       s->reserve(seq.size());
+                       
+                       // copy parts of seq which are known not to have changed
+                       epvector::const_iterator cit2 = seq.begin();
+                       while (cit2!=cit) {
+                               s->push_back(*cit2);
+                               ++cit2;
+                       }
+
+                       // copy first changed element
+                       s->push_back(combine_ex_with_coeff_to_pair(expanded_ex,
+                                                                  cit2->coeff));
+                       ++cit2;
+
+                       // copy rest
+                       while (cit2!=last) {
+                               s->push_back(combine_ex_with_coeff_to_pair(cit2->rest.expand(options),
+                                                                          cit2->coeff));
+                               ++cit2;
+                       }
+                       return s;
+               }
+               ++cit;
+       }
+       
+       return std::auto_ptr<epvector>(0); // signalling nothing has changed
+}
+
+
+/** Member-wise evaluate the expairs in this sequence.
+ *
+ *  @see expairseq::eval()
+ *  @return pointer to epvector containing evaluated pairs or zero pointer,
+ *  if no members were changed. */
+std::auto_ptr<epvector> expairseq::evalchildren(int level) const
+{
+       // returns a NULL pointer if nothing had to be evaluated
+       // returns a pointer to a newly created epvector otherwise
+       // (which has to be deleted somewhere else)
+
+       if (level==1)
+               return std::auto_ptr<epvector>(0);
+       
+       if (level == -max_recursion_level)
+               throw(std::runtime_error("max recursion level reached"));
+       
+       --level;
+       epvector::const_iterator last = seq.end();
+       epvector::const_iterator cit = seq.begin();
+       while (cit!=last) {
+               const ex &evaled_ex = cit->rest.eval(level);
+               if (!are_ex_trivially_equal(cit->rest,evaled_ex)) {
+                       
+                       // something changed, copy seq, eval and return it
+                       std::auto_ptr<epvector> s(new epvector);
+                       s->reserve(seq.size());
+                       
+                       // copy parts of seq which are known not to have changed
+                       epvector::const_iterator cit2=seq.begin();
+                       while (cit2!=cit) {
+                               s->push_back(*cit2);
+                               ++cit2;
+                       }
+
+                       // copy first changed element
+                       s->push_back(combine_ex_with_coeff_to_pair(evaled_ex,
+                                                                  cit2->coeff));
+                       ++cit2;
+
+                       // copy rest
+                       while (cit2!=last) {
+                               s->push_back(combine_ex_with_coeff_to_pair(cit2->rest.eval(level),
+                                                                          cit2->coeff));
+                               ++cit2;
+                       }
+                       return s;
+               }
+               ++cit;
+       }
+       
+       return std::auto_ptr<epvector>(0); // signalling nothing has changed
+}
+
+/** Member-wise substitute in this sequence.
+ *
+ *  @see expairseq::subs()
+ *  @return pointer to epvector containing pairs after application of subs,
+ *    or NULL pointer if no members were changed. */
+std::auto_ptr<epvector> expairseq::subschildren(const exmap & m, unsigned options) const
+{
+       // When any of the objects to be substituted is a product or power
+       // we have to recombine the pairs because the numeric coefficients may
+       // be part of the search pattern.
+       if (!(options & (subs_options::pattern_is_product | subs_options::pattern_is_not_product))) {
+
+               // Search the list of substitutions and cache our findings
+               for (exmap::const_iterator it = m.begin(); it != m.end(); ++it) {
+                       if (is_exactly_a<mul>(it->first) || is_exactly_a<power>(it->first)) {
+                               options |= subs_options::pattern_is_product;
+                               break;
+                       }
+               }
+               if (!(options & subs_options::pattern_is_product))
+                       options |= subs_options::pattern_is_not_product;
+       }
+
+       if (options & subs_options::pattern_is_product) {
+
+               // Substitute in the recombined pairs
+               epvector::const_iterator cit = seq.begin(), last = seq.end();
+               while (cit != last) {
+
+                       const ex &orig_ex = recombine_pair_to_ex(*cit);
+                       const ex &subsed_ex = orig_ex.subs(m, options);
+                       if (!are_ex_trivially_equal(orig_ex, subsed_ex)) {
+
+                               // Something changed, copy seq, subs and return it
+                               std::auto_ptr<epvector> s(new epvector);
+                               s->reserve(seq.size());
+
+                               // Copy parts of seq which are known not to have changed
+                               s->insert(s->begin(), seq.begin(), cit);
+
+                               // Copy first changed element
+                               s->push_back(split_ex_to_pair(subsed_ex));
+                               ++cit;
+
+                               // Copy rest
+                               while (cit != last) {
+                                       s->push_back(split_ex_to_pair(recombine_pair_to_ex(*cit).subs(m, options)));
+                                       ++cit;
+                               }
+                               return s;
+                       }
+
+                       ++cit;
+               }
+
+       } else {
+
+               // Substitute only in the "rest" part of the pairs
+               epvector::const_iterator cit = seq.begin(), last = seq.end();
+               while (cit != last) {
+
+                       const ex &subsed_ex = cit->rest.subs(m, options);
+                       if (!are_ex_trivially_equal(cit->rest, subsed_ex)) {
+                       
+                               // Something changed, copy seq, subs and return it
+                               std::auto_ptr<epvector> s(new epvector);
+                               s->reserve(seq.size());
+
+                               // Copy parts of seq which are known not to have changed
+                               s->insert(s->begin(), seq.begin(), cit);
+                       
+                               // Copy first changed element
+                               s->push_back(combine_ex_with_coeff_to_pair(subsed_ex, cit->coeff));
+                               ++cit;
+
+                               // Copy rest
+                               while (cit != last) {
+                                       s->push_back(combine_ex_with_coeff_to_pair(cit->rest.subs(m, options), cit->coeff));
+                                       ++cit;
+                               }
+                               return s;
+                       }
+
+                       ++cit;
+               }
+       }
+       
+       // Nothing has changed
+       return std::auto_ptr<epvector>(0);
 }
-*/
 
 //////////
 // static member variables
 //////////
 
-// protected
-
-unsigned expairseq::precedence=10;
-
-#ifdef EXPAIRSEQ_USE_HASHTAB
-unsigned expairseq::maxhashtabsize=0x4000000U;
-unsigned expairseq::minhashtabsize=0x1000U;
-unsigned expairseq::hashtabfactor=1;
-#endif // def EXPAIRSEQ_USE_HASHTAB
-
-//////////
-// global constants
-//////////
-
-const expairseq some_expairseq;
-type_info const & typeid_expairseq=typeid(some_expairseq);
+#if EXPAIRSEQ_USE_HASHTAB
+unsigned expairseq::maxhashtabsize = 0x4000000U;
+unsigned expairseq::minhashtabsize = 0x1000U;
+unsigned expairseq::hashtabfactor = 1;
+#endif // EXPAIRSEQ_USE_HASHTAB
 
+} // namespace GiNaC