Happy New Year!
[ginac.git] / ginac / relational.cpp
index 9dad5cc..92b5431 100644 (file)
@@ -1,8 +1,9 @@
 /** @file relational.cpp
  *
- *  Implementation of relations between expressions
- *
- *  GiNaC Copyright (C) 1999 Johannes Gutenberg University Mainz, Germany
+ *  Implementation of relations between expressions */
+
+/*
+ *  GiNaC Copyright (C) 1999-2019 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 "relational.h"
+#include "operators.h"
+#include "numeric.h"
+#include "archive.h"
+#include "utils.h"
+#include "hash_seed.h"
+
+#include <iostream>
 #include <stdexcept>
 
-#include "ginac.h"
+namespace GiNaC {
+
+GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(relational, basic,
+  print_func<print_context>(&relational::do_print).
+  print_func<print_tree>(&relational::do_print_tree).
+  print_func<print_python_repr>(&relational::do_print_python_repr))
 
 //////////
-// default constructor, destructor, copy constructor assignment operator and helpers
+// default constructor
 //////////
 
-// public
+relational::relational() { }
 
-relational::relational() : basic(TINFO_RELATIONAL)
-{
-    debugmsg("relational default constructor",LOGLEVEL_CONSTRUCT);
-}
-
-relational::~relational()
-{
-    debugmsg("relational destructor",LOGLEVEL_DESTRUCT);
-    destroy(0);
-}
+//////////
+// other constructors
+//////////
 
-relational::relational(relational const & other)
-{
-    debugmsg("relational copy constructor",LOGLEVEL_CONSTRUCT);
-    copy(other);
-}
+// public
 
-relational const & relational::operator=(relational const & other)
-{
-    debugmsg("relational operator=",LOGLEVEL_ASSIGNMENT);
-    if (this != &other) {
-        destroy(1);
-        copy(other);
-    }
-    return *this;
-}
+relational::relational(const ex & lhs, const ex & rhs, operators oper) :
+       lh(lhs), rh(rhs), o(oper) { }
 
-// protected
+//////////
+// archiving
+//////////
 
-void relational::copy(relational const & other)
+void relational::read_archive(const archive_node& n, lst& sym_lst)
 {
-    basic::copy(other);
-    lh=other.lh;
-    rh=other.rh;
-    o=other.o;
+       inherited::read_archive(n, sym_lst);
+       unsigned int opi;
+       if (!(n.find_unsigned("op", opi)))
+               throw (std::runtime_error("unknown relational operator in archive"));
+       o = (operators)opi;
+       n.find_ex("lh", lh, sym_lst);
+       n.find_ex("rh", rh, sym_lst);
 }
+GINAC_BIND_UNARCHIVER(relational);
 
-void relational::destroy(bool call_parent)
+void relational::archive(archive_node &n) const
 {
-    if (call_parent) basic::destroy(call_parent);
+       inherited::archive(n);
+       n.add_ex("lh", lh);
+       n.add_ex("rh", rh);
+       n.add_unsigned("op", o);
 }
 
 //////////
-// other constructors
+// functions overriding virtual functions from base classes
 //////////
 
 // public
 
-relational::relational(ex const & lhs, ex const & rhs, operators oper) : basic(TINFO_RELATIONAL)
+static void print_operator(const print_context & c, relational::operators o)
 {
-    debugmsg("relational constructor ex,ex,operator",LOGLEVEL_CONSTRUCT);
-    lh=lhs;
-    rh=rhs;
-    o=oper;
+       switch (o) {
+       case relational::equal:
+               c.s << "==";
+               break;
+       case relational::not_equal:
+               c.s << "!=";
+               break;
+       case relational::less:
+               c.s << "<";
+               break;
+       case relational::less_or_equal:
+               c.s << "<=";
+               break;
+       case relational::greater:
+               c.s << ">";
+               break;
+       case relational::greater_or_equal:
+               c.s << ">=";
+               break;
+       default:
+               c.s << "(INVALID RELATIONAL OPERATOR)";
+               break;
+       }
 }
 
-//////////
-// functions overriding virtual functions from bases classes
-//////////
-
-// public
+void relational::do_print(const print_context & c, unsigned level) const
+{
+       if (precedence() <= level)
+               c.s << "(";
+       lh.print(c, precedence());
+       print_operator(c, o);
+       rh.print(c, precedence());
+       if (precedence() <= level)
+               c.s << ")";
+}
 
-basic * relational::duplicate() const
+void relational::do_print_python_repr(const print_python_repr & c, unsigned level) const
 {
-    debugmsg("relational duplicate",LOGLEVEL_DUPLICATE);
-    return new relational(*this);
+       c.s << class_name() << '(';
+       lh.print(c);
+       c.s << ',';
+       rh.print(c);
+       c.s << ",'";
+       print_operator(c, o);
+       c.s << "')";
 }
 
 bool relational::info(unsigned inf) const
 {
-    switch (inf) {
-    case info_flags::relation:
-        return 1;
-    case info_flags::relation_equal:
-        return o==equal;
-    case info_flags::relation_not_equal:
-        return o==not_equal;
-    case info_flags::relation_less:
-        return o==less;
-    case info_flags::relation_less_or_equal:
-        return o==less_or_equal;
-    case info_flags::relation_greater:
-        return o==greater;
-    case info_flags::relation_greater_or_equal:
-        return o==greater_or_equal;
-    }
-    return 0;
+       switch (inf) {
+               case info_flags::relation:
+                       return 1;
+               case info_flags::relation_equal:
+                       return o==equal;
+               case info_flags::relation_not_equal:
+                       return o==not_equal;
+               case info_flags::relation_less:
+                       return o==less;
+               case info_flags::relation_less_or_equal:
+                       return o==less_or_equal;
+               case info_flags::relation_greater:
+                       return o==greater;
+               case info_flags::relation_greater_or_equal:
+                       return o==greater_or_equal;
+       }
+       return 0;
 }
 
-int relational::nops() const
+size_t relational::nops() const
 {
-    return 2;
+       return 2;
 }
 
-ex & relational::let_op(int const i)
+ex relational::op(size_t i) const
 {
-    ASSERT(i>=0);
-    ASSERT(i<2);
+       GINAC_ASSERT(i<2);
 
-    return i==0 ? lh : rh;
+       return i==0 ? lh : rh;
 }
-    
-ex relational::eval(int level) const
+
+ex relational::map(map_function & f) const
 {
-    if (level==1) {
-        return this->hold();
-    }
-    if (level == -max_recursion_level) {
-        throw(std::runtime_error("max recursion level reached"));
-    }
-    return (new relational(lh.eval(level-1),rh.eval(level-1),o))->
-            setflag(status_flags::dynallocated  |
-                    status_flags::evaluated );
+       const ex &mapped_lh = f(lh);
+       const ex &mapped_rh = f(rh);
+
+       if (!are_ex_trivially_equal(lh, mapped_lh)
+        || !are_ex_trivially_equal(rh, mapped_rh))
+               return dynallocate<relational>(mapped_lh, mapped_rh, o);
+       else
+               return *this;
 }
 
-ex relational::evalf(int level) const
+ex relational::subs(const exmap & m, unsigned options) const
 {
-    if (level==1) {
-        return *this;
-    }
-    if (level == -max_recursion_level) {
-        throw(std::runtime_error("max recursion level reached"));
-    }
-    return (new relational(lh.eval(level-1),rh.eval(level-1),o))->
-            setflag(status_flags::dynallocated);
+       const ex & subsed_lh = lh.subs(m, options);
+       const ex & subsed_rh = rh.subs(m, options);
+
+       if (!are_ex_trivially_equal(lh, subsed_lh) || !are_ex_trivially_equal(rh, subsed_rh))
+               return relational(subsed_lh, subsed_rh, o).subs_one_level(m, options);
+       else
+               return subs_one_level(m, options);
 }
 
-ex relational::simplify_ncmul(exvector const & v) const
+ex relational::eval_ncmul(const exvector & v) const
 {
-    return lh.simplify_ncmul(v);
+       return lh.eval_ncmul(v);
 }
 
 // protected
 
-int relational::compare_same_type(basic const & other) const
+int relational::compare_same_type(const basic & other) const
 {
-    ASSERT(is_exactly_of_type(other, relational));
-    relational const & oth=static_cast<relational const &>(const_cast<basic &>(other));
-    
-    int cmpval;
-    
-    if (o == oth.o) {
-        cmpval=lh.compare(oth.lh);
-        if (cmpval==0) {
-            return rh.compare(oth.rh);
-        } else {
-            return cmpval;
-        }
-    }
-    if (o<oth.o) {
-        return -1;
-    } else {
-        return 1;
-    }
+       GINAC_ASSERT(is_exactly_a<relational>(other));
+       const relational &oth = static_cast<const relational &>(other);
+       if (o==oth.o && lh.is_equal(oth.lh) && rh.is_equal(oth.rh))
+               return 0;
+       switch (o) {
+               case equal:
+               case not_equal:
+                       if (oth.o!=o)
+                               return (o < oth.o) ? -1 : 1;
+                       break;
+               case less:
+                       if (oth.o!=greater)
+                               return (o < oth.o) ? -1 : 1;
+                       break;
+               case less_or_equal:
+                       if (oth.o!=greater_or_equal)
+                               return (o < oth.o) ? -1 : 1;
+                       break;
+               case greater:
+                       if (oth.o!=less)
+                               return (o < oth.o) ? -1 : 1;
+                       break;
+               case greater_or_equal:
+                       if (oth.o!=less_or_equal)
+                               return (o < oth.o) ? -1 : 1;
+                       break;
+       }
+       const int lcmpval = lh.compare(oth.rh);
+       return (lcmpval!=0) ? lcmpval : rh.compare(oth.lh);
 }
 
-unsigned relational::return_type(void) const
+bool relational::match_same_type(const basic & other) const
 {
-    ASSERT(lh.return_type()==rh.return_type());
-    return lh.return_type();
+       GINAC_ASSERT(is_exactly_a<relational>(other));
+       const relational &oth = static_cast<const relational &>(other);
+
+       return o == oth.o;
 }
-   
-unsigned relational::return_type_tinfo(void) const
+
+unsigned relational::return_type() const
+{
+       GINAC_ASSERT(lh.return_type()==rh.return_type());
+       return lh.return_type();
+}
+
+return_type_t relational::return_type_tinfo() const
+{
+       GINAC_ASSERT(lh.return_type_tinfo()==rh.return_type_tinfo());
+       return lh.return_type_tinfo();
+}
+
+unsigned relational::calchash() const
 {
-    ASSERT(lh.return_type_tinfo()==rh.return_type_tinfo());
-    return lh.return_type_tinfo();
+       unsigned v = make_hash_seed(typeid(*this));
+       unsigned lhash = lh.gethash();
+       unsigned rhash = rh.gethash();
+
+       v = rotate_left(v);
+       switch(o) {
+               case equal:
+               case not_equal:
+                       if (lhash>rhash) {
+                               v ^= lhash;
+                               lhash = rhash;
+                       } else {
+                               v ^= rhash;
+                       }
+                       break;
+               case less:
+               case less_or_equal:
+                       v ^= rhash;
+                       break;
+               case greater:
+               case greater_or_equal:
+                       v ^= lhash;
+                       lhash = rhash;
+                       break;
+       }
+       v = rotate_left(v);
+       v ^= lhash;
+
+       // store calculated hash value only if object is already evaluated
+       if (flags & status_flags::evaluated) {
+               setflag(status_flags::hash_calculated);
+               hashvalue = v;
+       }
+
+       return v;
 }
 
 //////////
@@ -207,55 +296,39 @@ unsigned relational::return_type_tinfo(void) const
 // non-virtual functions in this class
 //////////
 
-#include <iostream>
-
-relational::operator bool() const
+relational::safe_bool relational::make_safe_bool(bool cond) const
 {
-    // please note that (a<b) == false does not imply (a>=b) == true
-    // a false result means the comparison is either false or undecidable
-    // (except for !=, where true means unequal or undecidable)
-    ex df=lh-rh;
-    if (!is_ex_exactly_of_type(df,numeric)) {
-        return o==not_equal ? true : false; // cannot decide on non-numerical results
-    }
-    int cmpval=ex_to_numeric(df).compare(numZERO());
-    switch (o) {
-    case equal:
-        return cmpval==0;
-        break;
-    case not_equal:
-        return cmpval!=0;
-        break;
-    case less:
-        return cmpval<0;
-        break;
-    case less_or_equal:
-        return cmpval<=0;
-        break;
-    case greater:
-        return cmpval>0;
-        break;
-    case greater_or_equal:
-        return cmpval>=0;
-        break;
-    default:
-        throw(std::logic_error("invalid relational operator"));
-    }
-    return 0;
+       return cond? &safe_bool_helper::nonnull : nullptr;
 }
 
-//////////
-// static member variables
-//////////
-
-// protected
-
-unsigned relational::precedence=20;
-
-//////////
-// global constants
-//////////
-
-const relational some_relational;
-type_info const & typeid_relational=typeid(some_relational);
+/** Cast the relational into a Boolean, mainly for evaluation within an
+ *  if-statement.  Note that (a<b) == false does not imply (a>=b) == true in
+ *  the general symbolic case.  A false result means the comparison is either
+ *  false or undecidable (except of course for !=, where true means either
+ *  unequal or undecidable). */
+relational::operator relational::safe_bool() const
+{
+       const ex df = lh-rh;
+       if (!is_exactly_a<numeric>(df))
+               // cannot decide on non-numerical results
+               return o==not_equal ? make_safe_bool(true) : make_safe_bool(false);
+
+       switch (o) {
+               case equal:
+                       return make_safe_bool(ex_to<numeric>(df).is_zero());
+               case not_equal:
+                       return make_safe_bool(!ex_to<numeric>(df).is_zero());
+               case less:
+                       return make_safe_bool(ex_to<numeric>(df)<(*_num0_p));
+               case less_or_equal:
+                       return make_safe_bool(ex_to<numeric>(df)<=(*_num0_p));
+               case greater:
+                       return make_safe_bool(ex_to<numeric>(df)>(*_num0_p));
+               case greater_or_equal:
+                       return make_safe_bool(ex_to<numeric>(df)>=(*_num0_p));
+               default:
+                       throw(std::logic_error("invalid relational operator"));
+       }
+}
 
+} // namespace GiNaC