Add support for Texinfo-5.0.

[ginac.git] / ginac / indexed.cpp

diff --git a/ginac/indexed.cpp b/ginac/indexed.cpp
index 0360d3416fc9f5c372b933efd4ffba427807f006..b85c38699b544d0cb30c56abac9f1f76f57d513f 100644 (file)
--- a/ginac/indexed.cpp
+++ b/ginac/indexed.cpp
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's indexed expressions. */
 
 /*
- *  GiNaC Copyright (C) 1999-2009 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
@@ -797,6 +797,7 @@ ex simplify_indexed_product(const ex & e, exvector & free_indices, exvector & du
 
        // Perform contractions
        bool something_changed = false;
+       bool has_nonsymmetric = false;
        GINAC_ASSERT(v.size() > 1);
        exvector::iterator it1, itend = v.end(), next_to_last = itend - 1;
        for (it1 = v.begin(); it1 != next_to_last; it1++) {
@@ -806,6 +807,7 @@ try_again:
                        continue;
 
                bool first_noncommutative = (it1->return_type() != return_types::commutative);
+               bool first_nonsymmetric = ex_to<symmetry>(ex_to<indexed>(*it1).get_symmetry()).has_nonsymmetric();
 
                // Indexed factor found, get free indices and look for contraction
                // candidates
@@ -882,6 +884,11 @@ contraction_done:
                                something_changed = true;
                                goto try_again;
                        }
+                       else if (!has_nonsymmetric &&
+                                       (first_nonsymmetric ||
+                                        ex_to<symmetry>(ex_to<indexed>(*it2).get_symmetry()).has_nonsymmetric())) {
+                               has_nonsymmetric = true;
+                       }
                }
        }
 
@@ -935,20 +942,22 @@ contraction_done:
        // The result should be symmetric with respect to exchange of dummy
        // indices, so if the symmetrization vanishes, the whole expression is
        // zero. This detects things like eps.i.j.k * p.j * p.k = 0.
-       ex q = idx_symmetrization<idx>(r, local_dummy_indices);
-       if (q.is_zero()) {
-               free_indices.clear();
-               return _ex0;
-       }
-       q = idx_symmetrization<varidx>(q, local_dummy_indices);
-       if (q.is_zero()) {
-               free_indices.clear();
-               return _ex0;
-       }
-       q = idx_symmetrization<spinidx>(q, local_dummy_indices);
-       if (q.is_zero()) {
-               free_indices.clear();
-               return _ex0;
+       if (has_nonsymmetric) {
+               ex q = idx_symmetrization<idx>(r, local_dummy_indices);
+               if (q.is_zero()) {
+                       free_indices.clear();
+                       return _ex0;
+               }
+               q = idx_symmetrization<varidx>(q, local_dummy_indices);
+               if (q.is_zero()) {
+                       free_indices.clear();
+                       return _ex0;
+               }
+               q = idx_symmetrization<spinidx>(q, local_dummy_indices);
+               if (q.is_zero()) {
+                       free_indices.clear();
+                       return _ex0;
+               }
        }
 
        // Dummy index renaming