Allow, optionally, indices to be substituted by things that are not indices.

[ginac.git] / ginac / idx.cpp

diff --git a/ginac/idx.cpp b/ginac/idx.cpp
index 67603cf271fb7efca16b0e76d8f1420fe53af2b2..73af6aac1333e588b6b05bcc5b7e9bdf3c19c37c 100644 (file)
--- a/ginac/idx.cpp
+++ b/ginac/idx.cpp
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's indices. */
 
 /*
- *  GiNaC Copyright (C) 1999-2003 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2006 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
@@ -17,7 +17,7 @@
  *
  *  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>
@@ -41,7 +41,7 @@ GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(idx, basic,
 
 GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(varidx, idx,
   print_func<print_context>(&varidx::do_print).
-  // print_latex inherited from idx
+  print_func<print_latex>(&varidx::do_print_latex).
   print_func<print_tree>(&varidx::do_print_tree))
 
 GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(spinidx, varidx,
@@ -53,23 +53,23 @@ GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(spinidx, varidx,
 // default constructor
 //////////
 
-idx::idx() : inherited(TINFO_idx) {}
+idx::idx() : inherited(&idx::tinfo_static) {}
 
 varidx::varidx() : covariant(false)
 {
-       tinfo_key = TINFO_varidx;
+       tinfo_key = &varidx::tinfo_static;
 }
 
 spinidx::spinidx() : dotted(false)
 {
-       tinfo_key = TINFO_spinidx;
+       tinfo_key = &spinidx::tinfo_static;
 }
 
 //////////
 // other constructors
 //////////
 
-idx::idx(const ex & v, const ex & d) : inherited(TINFO_idx), value(v), dim(d)
+idx::idx(const ex & v, const ex & d) : inherited(&idx::tinfo_static), value(v), dim(d)
 {
        if (is_dim_numeric())
                if (!dim.info(info_flags::posint))
@@ -78,12 +78,12 @@ idx::idx(const ex & v, const ex & d) : inherited(TINFO_idx), value(v), dim(d)
 
 varidx::varidx(const ex & v, const ex & d, bool cov) : inherited(v, d), covariant(cov)
 {
-       tinfo_key = TINFO_varidx;
+       tinfo_key = &varidx::tinfo_static;
 }
 
 spinidx::spinidx(const ex & v, const ex & d, bool cov, bool dot) : inherited(v, d, cov), dotted(dot)
 {
-       tinfo_key = TINFO_spinidx;
+       tinfo_key = &spinidx::tinfo_static;
 }
 
 //////////
@@ -242,11 +242,16 @@ ex idx::op(size_t i) const
 
 ex idx::map(map_function & f) const
 {
-       idx *copy = duplicate();
-       copy->setflag(status_flags::dynallocated);
-       copy->clearflag(status_flags::hash_calculated);
-       copy->value = f(value);
-       return *copy;
+       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;
+       }
 }
 
 /** Returns order relation between two indices of the same type. The order
@@ -325,11 +330,17 @@ bool spinidx::match_same_type(const basic & other) const
 
 unsigned idx::calchash() const
 {
-       unsigned v = golden_ratio_hash(tinfo());
+       // 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 = golden_ratio_hash((p_int)tinfo());
        v = rotate_left(v);
        v ^= value.gethash();
-       v = rotate_left(v);
-       v ^= dim.gethash();
 
        // Store calculated hash value only if object is already evaluated
        if (flags & status_flags::evaluated) {
@@ -354,7 +365,7 @@ ex idx::subs(const exmap & m, unsigned options) const
        if (it != m.end()) {
 
                // Substitution index->index
-               if (is_a<idx>(it->second))
+               if (is_a<idx>(it->second) || (options & subs_options::really_subs_idx))
                        return it->second;
 
                // Otherwise substitute value
@@ -404,7 +415,7 @@ bool idx::is_dummy_pair_same_type(const basic & other) const
        if (dim.is_equal(o.dim))
                return true;
 
-       return (dim < o.dim || dim > o.dim || (is_exactly_a<numeric>(dim) && is_a<symbol>(o.dim)) || (is_a<symbol>(dim) && is_exactly_a<numeric>(o.dim)));
+       return is_exactly_a<numeric>(dim) || is_exactly_a<numeric>(o.dim);
 }
 
 bool varidx::is_dummy_pair_same_type(const basic & other) const
@@ -537,9 +548,9 @@ void find_free_and_dummy(exvector::const_iterator it, exvector::const_iterator i
 
 ex minimal_dim(const ex & dim1, const ex & dim2)
 {
-       if (dim1.is_equal(dim2) || dim1 < dim2 || (is_exactly_a<numeric>(dim1) && is_a<symbol>(dim2)))
+       if (dim1.is_equal(dim2) || dim1 < dim2 || (is_exactly_a<numeric>(dim1) && !is_a<numeric>(dim2)))
                return dim1;
-       else if (dim1 > dim2 || (is_a<symbol>(dim1) && is_exactly_a<numeric>(dim2)))
+       else if (dim1 > dim2 || (!is_a<numeric>(dim1) && is_exactly_a<numeric>(dim2)))
                return dim2;
        else {
                std::ostringstream s;