]> www.ginac.de Git - ginac.git/blobdiff - ginac/idx.cpp
Transform abs(x)^n => x^n if x is real and n is even.
[ginac.git] / ginac / idx.cpp
index 2fc851c78aa6e9afa411f0df2ec834fce4d81a9b..a3f0b843f153fefc8da3be335e5510e9f2d23c1b 100644 (file)
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's indices. */
 
 /*
- *  GiNaC Copyright (C) 1999-2001 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2011 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 <stdexcept>
-
 #include "idx.h"
-#include "ex.h"
+#include "symbol.h"
 #include "lst.h"
 #include "relational.h"
+#include "operators.h"
 #include "archive.h"
 #include "utils.h"
-#include "debugmsg.h"
+#include "hash_seed.h"
+
+#include <iostream>
+#include <sstream>
+#include <stdexcept>
 
-#ifndef NO_NAMESPACE_GINAC
 namespace GiNaC {
-#endif // ndef NO_NAMESPACE_GINAC
 
-GINAC_IMPLEMENT_REGISTERED_CLASS(idx, basic)
+GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(idx, basic,
+  print_func<print_context>(&idx::do_print).
+  print_func<print_latex>(&idx::do_print_latex).
+  print_func<print_csrc>(&idx::do_print_csrc).
+  print_func<print_tree>(&idx::do_print_tree))
+
+GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(varidx, idx,
+  print_func<print_context>(&varidx::do_print).
+  print_func<print_latex>(&varidx::do_print_latex).
+  print_func<print_tree>(&varidx::do_print_tree))
+
+GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(spinidx, varidx,
+  print_func<print_context>(&spinidx::do_print).
+  print_func<print_latex>(&spinidx::do_print_latex).
+  print_func<print_tree>(&spinidx::do_print_tree))
 
 //////////
-// default constructor, destructor, copy constructor assignment operator and helpers
+// default constructor
 //////////
 
-// public
+idx::idx() {}
 
-idx::idx() : inherited(TINFO_idx), symbolic(true), covariant(false)
+varidx::varidx() : covariant(false)
 {
-       debugmsg("idx default constructor",LOGLEVEL_CONSTRUCT);
-       serial=next_serial++;
-       name="index"+ToString(serial);
 }
 
-idx::~idx() 
+spinidx::spinidx() : dotted(false)
 {
-       debugmsg("idx destructor",LOGLEVEL_DESTRUCT);
-       destroy(false);
 }
 
-idx::idx(const idx & other)
-{
-       debugmsg("idx copy constructor",LOGLEVEL_CONSTRUCT);
-       copy(other);
-}
+//////////
+// other constructors
+//////////
 
-const idx & idx::operator=(const idx & other)
+idx::idx(const ex & v, const ex & d) :  value(v), dim(d)
 {
-       debugmsg("idx operator=",LOGLEVEL_ASSIGNMENT);
-       if (this != &other) {
-               destroy(true);
-               copy(other);
-       }
-       return *this;
+       if (is_dim_numeric())
+               if (!dim.info(info_flags::posint))
+                       throw(std::invalid_argument("dimension of space must be a positive integer"));
 }
 
-// protected
-
-void idx::copy(const idx & other)
+varidx::varidx(const ex & v, const ex & d, bool cov) : inherited(v, d), covariant(cov)
 {
-       inherited::copy(other);
-       serial=other.serial;
-       symbolic=other.symbolic;
-       name=other.name;
-       value=other.value;
-       covariant=other.covariant;
 }
 
-void idx::destroy(bool call_parent)
+spinidx::spinidx(const ex & v, const ex & d, bool cov, bool dot) : inherited(v, d, cov), dotted(dot)
 {
-       if (call_parent) inherited::destroy(call_parent);
 }
 
 //////////
-// other constructors
+// archiving
 //////////
 
-// public
+void idx::read_archive(const archive_node& n, lst& sym_lst) 
+{
+       inherited::read_archive(n, sym_lst);
+       n.find_ex("value", value, sym_lst);
+       n.find_ex("dim", dim, sym_lst);
+}
+GINAC_BIND_UNARCHIVER(idx);
+
+void varidx::read_archive(const archive_node& n, lst& sym_lst)
+{
+       inherited::read_archive(n, sym_lst);
+       n.find_bool("covariant", covariant);
+}
+GINAC_BIND_UNARCHIVER(varidx);
 
-idx::idx(bool cov) : inherited(TINFO_idx), symbolic(true), covariant(cov)
+void spinidx::read_archive(const archive_node& n, lst& sym_lst)
 {
-       debugmsg("idx constructor from bool",LOGLEVEL_CONSTRUCT);
-       serial = next_serial++;
-       name = "index"+ToString(serial);
+       inherited::read_archive(n, sym_lst);
+       n.find_bool("dotted", dotted);
 }
+GINAC_BIND_UNARCHIVER(spinidx);
 
-idx::idx(const std::string & n, bool cov) : inherited(TINFO_idx),  
-       symbolic(true), name(n), covariant(cov)
+void idx::archive(archive_node &n) const
 {
-       debugmsg("idx constructor from string,bool",LOGLEVEL_CONSTRUCT);
-       serial = next_serial++;
+       inherited::archive(n);
+       n.add_ex("value", value);
+       n.add_ex("dim", dim);
 }
 
-idx::idx(const char * n, bool cov) : inherited(TINFO_idx), symbolic(true), name(n), covariant(cov)
+void varidx::archive(archive_node &n) const
 {
-       debugmsg("idx constructor from char*,bool",LOGLEVEL_CONSTRUCT);
-       serial = next_serial++;
+       inherited::archive(n);
+       n.add_bool("covariant", covariant);
 }
 
-idx::idx(unsigned v, bool cov) : inherited(TINFO_idx), symbolic(false), value(v), covariant(cov)
+void spinidx::archive(archive_node &n) const
 {
-       debugmsg("idx constructor from unsigned,bool",LOGLEVEL_CONSTRUCT);
-       serial = 0;
+       inherited::archive(n);
+       n.add_bool("dotted", dotted);
 }
 
 //////////
-// archiving
+// functions overriding virtual functions from base classes
 //////////
 
-/** Construct object from archive_node. */
-idx::idx(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
-{
-       debugmsg("idx constructor from archive_node", LOGLEVEL_CONSTRUCT);
-       n.find_bool("symbolic", symbolic);
-       n.find_bool("covariant", covariant);
-       if (symbolic) {
-               serial = next_serial++;
-               if (!(n.find_string("name", name)))
-                       name = "index" + ToString(serial);
-       } else {
-               serial = 0;
-               n.find_unsigned("value", value);
+void idx::print_index(const print_context & c, unsigned level) const
+{
+       bool need_parens = !(is_exactly_a<numeric>(value) || is_a<symbol>(value));
+       if (need_parens)
+               c.s << "(";
+       value.print(c);
+       if (need_parens)
+               c.s << ")";
+       if (c.options & print_options::print_index_dimensions) {
+               c.s << "[";
+               dim.print(c);
+               c.s << "]";
        }
 }
 
-/** Unarchive the object. */
-ex idx::unarchive(const archive_node &n, const lst &sym_lst)
+void idx::do_print(const print_context & c, unsigned level) const
 {
-       ex s = (new idx(n, sym_lst))->setflag(status_flags::dynallocated);
+       c.s << ".";
+       print_index(c, level);
+}
 
-       if (ex_to_idx(s).symbolic) {
-               // If idx is in sym_lst, return the existing idx
-               for (unsigned i=0; i<sym_lst.nops(); i++) {
-                       if (is_ex_of_type(sym_lst.op(i), idx) && (ex_to_idx(sym_lst.op(i)).name == ex_to_idx(s).name))
-                               return sym_lst.op(i);
-               }
-       }
-       return s;
+void idx::do_print_latex(const print_latex & c, unsigned level) const
+{
+       c.s << "{";
+       print_index(c, level);
+       c.s << "}";
 }
 
-/** Archive the object. */
-void idx::archive(archive_node &n) const
+void idx::do_print_csrc(const print_csrc & c, unsigned level) const
 {
-       inherited::archive(n);
-       n.add_bool("symbolic", symbolic);
-       n.add_bool("covariant", covariant);
-       if (symbolic)
-               n.add_string("name", name);
+       c.s << "[";
+       if (value.info(info_flags::integer))
+               c.s << ex_to<numeric>(value).to_int();
        else
-               n.add_unsigned("value", value);
+               value.print(c);
+       c.s << "]";
 }
 
-//////////
-// functions overriding virtual functions from bases classes
-//////////
+void idx::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
+           << std::endl;
+       value.print(c, level +  c.delta_indent);
+       dim.print(c, level + c.delta_indent);
+}
 
-// public
+void varidx::do_print(const print_context & c, unsigned level) const
+{
+       if (covariant)
+               c.s << ".";
+       else
+               c.s << "~";
+       print_index(c, level);
+}
 
-basic * idx::duplicate() const
+void varidx::do_print_tree(const print_tree & c, unsigned level) const
 {
-       debugmsg("idx duplicate",LOGLEVEL_DUPLICATE);
-       return new idx(*this);
+       c.s << std::string(level, ' ') << class_name() << " @" << this
+           << std::hex << ", hash=0x" << hashvalue << ", flags=0x" << flags << std::dec
+           << (covariant ? ", covariant" : ", contravariant")
+           << std::endl;
+       value.print(c, level + c.delta_indent);
+       dim.print(c, level + c.delta_indent);
 }
 
-void idx::printraw(std::ostream & os) const
+void spinidx::do_print(const print_context & c, unsigned level) const
 {
-       debugmsg("idx printraw",LOGLEVEL_PRINT);
+       if (covariant)
+               c.s << ".";
+       else
+               c.s << "~";
+       if (dotted)
+               c.s << "*";
+       print_index(c, level);
+}
 
-       os << "idx(";
+void spinidx::do_print_latex(const print_latex & c, unsigned level) const
+{
+       if (dotted)
+               c.s << "\\dot{";
+       else
+               c.s << "{";
+       print_index(c, level);
+       c.s << "}";
+}
 
-       if (symbolic) {
-               os << "symbolic,name=" << name;
-       } else {
-               os << "non symbolic,value=" << value;
-       }
+void spinidx::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
+           << (covariant ? ", covariant" : ", contravariant")
+           << (dotted ? ", dotted" : ", undotted")
+           << std::endl;
+       value.print(c, level + c.delta_indent);
+       dim.print(c, level + c.delta_indent);
+}
 
-       if (covariant) {
-               os << ",covariant";
-       } else {
-               os << ",contravariant";
+bool idx::info(unsigned inf) const
+{
+       switch(inf) {
+               case info_flags::idx:
+               case info_flags::has_indices:
+                       return true;
        }
-
-       os << ",serial=" << serial;
-       os << ",hash=" << hashvalue << ",flags=" << flags;
-       os << ")";
+       return inherited::info(inf);
 }
 
-void idx::printtree(std::ostream & os, unsigned indent) const
+size_t idx::nops() const
 {
-       debugmsg("idx printtree",LOGLEVEL_PRINT);
+       // don't count the dimension as that is not really a sub-expression
+       return 1;
+}
 
-       os << std::string(indent,' ') << "idx: ";
+ex idx::op(size_t i) const
+{
+       GINAC_ASSERT(i == 0);
+       return value;
+}
 
-       if (symbolic) {
-               os << "symbolic,name=" << name;
-       } else {
-               os << "non symbolic,value=" << value;
+ex idx::map(map_function & f) const
+{
+       const ex &mapped_value = f(value);
+       if (are_ex_trivially_equal(value, mapped_value))
+               return *this;
+       else {
+               idx *copy = duplicate();
+               copy->setflag(status_flags::dynallocated);
+               copy->clearflag(status_flags::hash_calculated);
+               copy->value = mapped_value;
+               return *copy;
        }
+}
 
-       if (covariant) {
-               os << ",covariant";
-       } else {
-               os << ",contravariant";
-       }
+/** Returns order relation between two indices of the same type. The order
+ *  must be such that dummy indices lie next to each other. */
+int idx::compare_same_type(const basic & other) const
+{
+       GINAC_ASSERT(is_a<idx>(other));
+       const idx &o = static_cast<const idx &>(other);
 
-       os << ", serial=" << serial
-          << ", hash=" << hashvalue
-          << " (0x" << std::hex << hashvalue << std::dec << ")"
-          << ", flags=" << flags << std::endl;
+       int cmpval = value.compare(o.value);
+       if (cmpval)
+               return cmpval;
+       return dim.compare(o.dim);
 }
 
-void idx::print(std::ostream & os, unsigned upper_precedence) const
+bool idx::match_same_type(const basic & other) const
 {
-       debugmsg("idx print",LOGLEVEL_PRINT);
+       GINAC_ASSERT(is_a<idx>(other));
+       const idx &o = static_cast<const idx &>(other);
 
-       if (covariant) {
-               os << "_";
-       } else {
-               os << "~";
-       }
-       if (symbolic) {
-               os << name;
-       } else {
-               os << value;
-       }
+       return dim.is_equal(o.dim);
 }
 
-bool idx::info(unsigned inf) const
+int varidx::compare_same_type(const basic & other) const
 {
-       if (inf==info_flags::idx) return true;
-       return inherited::info(inf);
+       GINAC_ASSERT(is_a<varidx>(other));
+       const varidx &o = static_cast<const varidx &>(other);
+
+       int cmpval = inherited::compare_same_type(other);
+       if (cmpval)
+               return cmpval;
+
+       // Check variance last so dummy indices will end up next to each other
+       if (covariant != o.covariant)
+               return covariant ? -1 : 1;
+
+       return 0;
 }
 
-ex idx::subs(const lst & ls, const lst & lr) const
+bool varidx::match_same_type(const basic & other) const
 {
-       GINAC_ASSERT(ls.nops()==lr.nops());
-#ifdef DO_GINAC_ASSERT
-       for (unsigned i=0; i<ls.nops(); i++) {
-               GINAC_ASSERT(is_ex_exactly_of_type(ls.op(i),symbol)||
-                          is_ex_of_type(ls.op(i),idx));
-       }
-#endif // def DO_GINAC_ASSERT
+       GINAC_ASSERT(is_a<varidx>(other));
+       const varidx &o = static_cast<const varidx &>(other);
 
-       for (unsigned i=0; i<ls.nops(); i++) {
-               if (is_equal(*(ls.op(i)).bp)) {
-                       return lr.op(i);
-               }
-       }
-       return *this;
+       if (covariant != o.covariant)
+               return false;
+
+       return inherited::match_same_type(other);
 }
 
-// protected
+int spinidx::compare_same_type(const basic & other) const
+{
+       GINAC_ASSERT(is_a<spinidx>(other));
+       const spinidx &o = static_cast<const spinidx &>(other);
 
-int idx::compare_same_type(const basic & other) const
+       // Check dottedness first so dummy indices will end up next to each other
+       if (dotted != o.dotted)
+               return dotted ? -1 : 1;
+
+       int cmpval = inherited::compare_same_type(other);
+       if (cmpval)
+               return cmpval;
+
+       return 0;
+}
+
+bool spinidx::match_same_type(const basic & other) const
 {
-       GINAC_ASSERT(is_of_type(other,idx));
-       const idx & o=static_cast<const idx &>(const_cast<basic &>(other));
+       GINAC_ASSERT(is_a<spinidx>(other));
+       const spinidx &o = static_cast<const spinidx &>(other);
 
-       if (covariant!=o.covariant) {
-               // different co/contravariant
-               return covariant ? -1 : 1;
-       }
-       if ((!symbolic) && (!o.symbolic)) {
-               // non-symbolic, of equal type: compare values
-               if (value==o.value) {
-                       return 0;
-               }
-               return value<o.value ? -1 : 1;
-       }
-       if (symbolic && o.symbolic) {
-               // both symbolic: compare serials
-               if (serial==o.serial) {
-                       return 0;
-               }
-               return serial<o.serial ? -1 : 1;
+       if (dotted != o.dotted)
+               return false;
+       return inherited::match_same_type(other);
+}
+
+unsigned idx::calchash() const
+{
+       // NOTE: The code in simplify_indexed() assumes that canonically
+       // ordered sequences of indices have the two members of dummy index
+       // pairs lying next to each other. The hash values for indices must
+       // be devised accordingly. The easiest (only?) way to guarantee the
+       // desired ordering is to make indices with the same value have equal
+       // hash keys. That is, the hash values must not depend on the index
+       // dimensions or other attributes (variance etc.).
+       // The compare_same_type() methods will take care of the rest.
+       unsigned v = make_hash_seed(typeid(*this));
+       v = rotate_left(v);
+       v ^= value.gethash();
+
+       // Store calculated hash value only if object is already evaluated
+       if (flags & status_flags::evaluated) {
+               setflag(status_flags::hash_calculated);
+               hashvalue = v;
        }
-       // one symbolic, one value: value is sorted first
-       return o.symbolic ? -1 : 1;
+
+       return v;
+}
+
+/** By default, basic::evalf would evaluate the index value but we don't want
+ *  a.1 to become a.(1.0). */
+ex idx::evalf(int level) const
+{
+       return *this;
 }
 
-bool idx::is_equal_same_type(const basic & other) const
+ex idx::subs(const exmap & m, unsigned options) const
 {
-       GINAC_ASSERT(is_of_type(other,idx));
-       const idx & o=static_cast<const idx &>(const_cast<basic &>(other));
+       // First look for index substitutions
+       exmap::const_iterator it = m.find(*this);
+       if (it != m.end()) {
+
+               // Substitution index->index
+               if (is_a<idx>(it->second) || (options & subs_options::really_subs_idx))
+                       return it->second;
+
+               // Otherwise substitute value
+               idx *i_copy = duplicate();
+               i_copy->value = it->second;
+               i_copy->clearflag(status_flags::hash_calculated);
+               return i_copy->setflag(status_flags::dynallocated);
+       }
+
+       // None, substitute objects in value (not in dimension)
+       const ex &subsed_value = value.subs(m, options);
+       if (are_ex_trivially_equal(value, subsed_value))
+               return *this;
 
-       if (covariant!=o.covariant) return false;
-       if (symbolic!=o.symbolic) return false;
-       if (symbolic && o.symbolic) return serial==o.serial;
-       return value==o.value;
-}    
+       idx *i_copy = duplicate();
+       i_copy->value = subsed_value;
+       i_copy->clearflag(status_flags::hash_calculated);
+       return i_copy->setflag(status_flags::dynallocated);
+}
 
-unsigned idx::calchash(void) const
+/** Implementation of ex::diff() for an index always returns 0.
+ *
+ *  @see ex::diff */
+ex idx::derivative(const symbol & s) const
 {
-       hashvalue=golden_ratio_hash(golden_ratio_hash(tinfo_key ^ serial));
-       setflag(status_flags::hash_calculated);
-       return hashvalue;
+       return _ex0;
 }
 
 //////////
-// new virtual functions which can be overridden by derived classes
+// new virtual functions
 //////////
 
-// public
+bool idx::is_dummy_pair_same_type(const basic & other) const
+{
+       const idx &o = static_cast<const idx &>(other);
 
-bool idx::is_co_contra_pair(const basic & other) const
+       // Only pure symbols form dummy pairs, "2n+1" doesn't
+       if (!is_a<symbol>(value))
+               return false;
+
+       // Value must be equal, of course
+       if (!value.is_equal(o.value))
+               return false;
+
+       // Dimensions need not be equal but must be comparable (so we can
+       // determine the minimum dimension of contractions)
+       if (dim.is_equal(o.dim))
+               return true;
+
+       return is_exactly_a<numeric>(dim) || is_exactly_a<numeric>(o.dim);
+}
+
+bool varidx::is_dummy_pair_same_type(const basic & other) const
 {
-       // like is_equal_same_type(), but tests for different covariant status
-       GINAC_ASSERT(is_of_type(other,idx));
-       const idx & o=static_cast<const idx &>(const_cast<basic &>(other));
+       const varidx &o = static_cast<const varidx &>(other);
 
-       if (covariant==o.covariant) return false;
-       if (symbolic!=o.symbolic) return false;
-       if (symbolic && o.symbolic) return serial==o.serial;
-       return value==o.value;
-}    
+       // Variance must be opposite
+       if (covariant == o.covariant)
+               return false;
 
-bool idx::is_symbolic(void) const
+       return inherited::is_dummy_pair_same_type(other);
+}
+
+bool spinidx::is_dummy_pair_same_type(const basic & other) const
 {
-       return symbolic;
+       const spinidx &o = static_cast<const spinidx &>(other);
+
+       // Dottedness must be the same
+       if (dotted != o.dotted)
+               return false;
+
+       return inherited::is_dummy_pair_same_type(other);
 }
 
-unsigned idx::get_value(void) const
+
+//////////
+// non-virtual functions
+//////////
+
+ex idx::replace_dim(const ex & new_dim) const
 {
-       return value;
+       idx *i_copy = duplicate();
+       i_copy->dim = new_dim;
+       i_copy->clearflag(status_flags::hash_calculated);
+       return i_copy->setflag(status_flags::dynallocated);
 }
 
-bool idx::is_covariant(void) const
+ex idx::minimal_dim(const idx & other) const
 {
-       return covariant;
+       return GiNaC::minimal_dim(dim, other.dim);
 }
 
-ex idx::toggle_covariant(void) const
+ex varidx::toggle_variance() const
 {
-       idx * i_copy=static_cast<idx *>(duplicate());
+       varidx *i_copy = duplicate();
        i_copy->covariant = !i_copy->covariant;
        i_copy->clearflag(status_flags::hash_calculated);
        return i_copy->setflag(status_flags::dynallocated);
 }
 
-//////////
-// non-virtual functions in this class
-//////////
+ex spinidx::toggle_dot() const
+{
+       spinidx *i_copy = duplicate();
+       i_copy->dotted = !i_copy->dotted;
+       i_copy->clearflag(status_flags::hash_calculated);
+       return i_copy->setflag(status_flags::dynallocated);
+}
 
-// none
+ex spinidx::toggle_variance_dot() const
+{
+       spinidx *i_copy = duplicate();
+       i_copy->covariant = !i_copy->covariant;
+       i_copy->dotted = !i_copy->dotted;
+       i_copy->clearflag(status_flags::hash_calculated);
+       return i_copy->setflag(status_flags::dynallocated);
+}
 
 //////////
-// static member variables
+// global functions
 //////////
 
-// protected
-
-unsigned idx::next_serial=0;
+bool is_dummy_pair(const idx & i1, const idx & i2)
+{
+       // The indices must be of exactly the same type
+       if (typeid(i1) != typeid(i2))
+               return false;
 
-//////////
-// global constants
-//////////
+       // Same type, let the indices decide whether they are paired
+       return i1.is_dummy_pair_same_type(i2);
+}
 
-const idx some_idx;
-const std::type_info & typeid_idx = typeid(some_idx);
+bool is_dummy_pair(const ex & e1, const ex & e2)
+{
+       // The expressions must be indices
+       if (!is_a<idx>(e1) || !is_a<idx>(e2))
+               return false;
 
-//////////
-// other functions
-//////////
+       return is_dummy_pair(ex_to<idx>(e1), ex_to<idx>(e2));
+}
 
-int canonicalize_indices(exvector & iv, bool antisymmetric)
+void find_free_and_dummy(exvector::const_iterator it, exvector::const_iterator itend, exvector & out_free, exvector & out_dummy)
 {
-       if (iv.size()<2) {
-               // nothing do to for 0 or 1 indices
-               return INT_MAX;
-       }
+       out_free.clear();
+       out_dummy.clear();
 
-       bool something_changed=false;
-       int sig=1;
-       // simple bubble sort algorithm should be sufficient for the small number of indices needed
-       exvector::const_iterator last_idx=iv.end();
-       exvector::const_iterator next_to_last_idx=iv.end()-1;
-       for (exvector::iterator it1=iv.begin(); it1!=next_to_last_idx; ++it1) {
-               for (exvector::iterator it2=it1+1; it2!=last_idx; ++it2) {
-                       int cmpval=(*it1).compare(*it2);
-                       if (cmpval==1) {
-                               iter_swap(it1,it2);
-                               something_changed=true;
-                               if (antisymmetric) sig=-sig;
-                       } else if ((cmpval==0) && antisymmetric) {
-                               something_changed=true;
-                               sig=0;
-                       }
-               }
-       }
-       return something_changed ? sig : INT_MAX;
-}
-
-exvector idx_intersect(const exvector & iv1, const exvector & iv2)
-{
-       // build a vector of symbolic indices contained in iv1 and iv2 simultaneously
-       // assumes (but does not test) that each index occurs at most twice
-       exvector iv_intersect;
-       for (exvector::const_iterator cit1=iv1.begin(); cit1!=iv1.end(); ++cit1) {
-               GINAC_ASSERT(is_ex_of_type(*cit1,idx));
-               if (ex_to_idx(*cit1).is_symbolic()) {
-                       for (exvector::const_iterator cit2=iv2.begin(); cit2!=iv2.end(); ++cit2) {
-                               GINAC_ASSERT(is_ex_of_type(*cit2,idx));
-                               if ((*cit1).is_equal(*cit2)) {
-                                       iv_intersect.push_back(*cit1);
-                                       break;
-                               }
-                       }
-               }
-       }
-       return iv_intersect;
-}
+       // No indices? Then do nothing
+       if (it == itend)
+               return;
 
-#define TEST_PERMUTATION(A,B,C,P) \
-       if ((iv3[B].is_equal(iv2[0]))&&(iv3[C].is_equal(iv2[1]))) { \
-               if (antisymmetric) *sig=P; \
-               return iv3[A]; \
+       // Only one index? Then it is a free one if it's not numeric
+       if (itend - it == 1) {
+               if (ex_to<idx>(*it).is_symbolic())
+                       out_free.push_back(*it);
+               return;
        }
 
-ex permute_free_index_to_front(const exvector & iv3, const exvector & iv2,
-                               bool antisymmetric, int * sig)
-{
-       // match (return value,iv2) to iv3 by permuting indices
-       // iv3 is always cyclic
-
-       GINAC_ASSERT(iv3.size()==3);
-       GINAC_ASSERT(iv2.size()==2);
-
-       *sig=1;
-       
-       TEST_PERMUTATION(0,1,2,  1);
-       TEST_PERMUTATION(0,2,1, -1);
-       TEST_PERMUTATION(1,0,2, -1);
-       TEST_PERMUTATION(1,2,0,  1);
-       TEST_PERMUTATION(2,0,1,  1);
-       TEST_PERMUTATION(2,1,0, -1);
-       throw(std::logic_error("permute_free_index_to_front(): no valid permutation found"));
-}
-       
-unsigned subs_index_in_exvector(exvector & v, const ex & is, const ex & ir)
-{
-       exvector::iterator it;
-       unsigned replacements=0;
-       unsigned current_replacements;
-
-       GINAC_ASSERT(is_ex_of_type(is,idx));
-       GINAC_ASSERT(is_ex_of_type(ir,idx));
-   
-       for (it=v.begin(); it!=v.end(); ++it) {
-               current_replacements=count_index(*it,is);
-               if (current_replacements>0) {
-                       (*it)=(*it).subs(is==ir);
+       // Sort index vector. This will cause dummy indices come to lie next
+       // to each other (because the sort order is defined to guarantee this).
+       exvector v(it, itend);
+       shaker_sort(v.begin(), v.end(), ex_is_less(), ex_swap());
+
+       // Find dummy pairs and free indices
+       it = v.begin(); itend = v.end();
+       exvector::const_iterator last = it++;
+       while (it != itend) {
+               if (is_dummy_pair(*it, *last)) {
+                       out_dummy.push_back(*last);
+                       it++;
+                       if (it == itend)
+                               return;
+               } else {
+                       if (!it->is_equal(*last) && ex_to<idx>(*last).is_symbolic())
+                               out_free.push_back(*last);
                }
-               replacements += current_replacements;
-       }
-       return replacements;
-}
-
-unsigned count_index(const ex & e, const ex & i)
-{
-       exvector idxv=e.get_indices();
-       unsigned count=0;
-       for (exvector::const_iterator cit=idxv.begin(); cit!=idxv.end(); ++cit) {
-               if ((*cit).is_equal(i)) count++;
+               last = it++;
        }
-       return count;
+       if (ex_to<idx>(*last).is_symbolic())
+               out_free.push_back(*last);
 }
 
-ex subs_indices(const ex & e, const exvector & idxv_subs,
-                const exvector & idxv_repl)
+ex minimal_dim(const ex & dim1, const ex & dim2)
 {
-       GINAC_ASSERT(idxv_subs.size()==idxv_repl.size());
-       ex res=e;
-       for (unsigned i=0; i<idxv_subs.size(); ++i) {
-               res=res.subs(idxv_subs[i]==idxv_repl[i]);
+       if (dim1.is_equal(dim2) || dim1 < dim2 || (is_exactly_a<numeric>(dim1) && !is_a<numeric>(dim2)))
+               return dim1;
+       else if (dim1 > dim2 || (!is_a<numeric>(dim1) && is_exactly_a<numeric>(dim2)))
+               return dim2;
+       else {
+               std::ostringstream s;
+               s << "minimal_dim(): index dimensions " << dim1 << " and " << dim2 << " cannot be ordered";
+               throw (std::runtime_error(s.str()));
        }
-       return res;
 }
 
-#ifndef NO_NAMESPACE_GINAC
 } // namespace GiNaC
-#endif // ndef NO_NAMESPACE_GINAC