X-Git-Url: https://ginac.de/ginac.git//ginac.git?a=blobdiff_plain;ds=sidebyside;f=ginac%2Findexed.cpp;h=873a9ad0b9661d721f14d09439ab8256661b7260;hb=e0a84a395ab1bf84813eea95fde9c8a361dae9bc;hp=01fc985bb60805bb4cc1f961ae8faff42d4f3965;hpb=d327f3f00c66a79d42855939866047b3e8caa630;p=ginac.git

diff --git a/ginac/indexed.cpp b/ginac/indexed.cpp
index 01fc985b..873a9ad0 100644
--- a/ginac/indexed.cpp
+++ b/ginac/indexed.cpp
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's indexed expressions. */
 
 /*
- *  GiNaC Copyright (C) 1999-2008 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2015 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
@@ -20,11 +20,6 @@
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
-#include <iostream>
-#include <sstream>
-#include <stdexcept>
-#include <limits>
-
 #include "indexed.h"
 #include "idx.h"
 #include "add.h"
@@ -42,6 +37,11 @@
 #include "matrix.h"
 #include "inifcns.h"
 
+#include <iostream>
+#include <limits>
+#include <sstream>
+#include <stdexcept>
+
 namespace GiNaC {
 
 GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(indexed, exprseq,
@@ -648,7 +648,7 @@ bool reposition_dummy_indices(ex & e, exvector & variant_dummy_indices, exvector
 	}
 
 	// In the case where a dummy symbol occurs twice in the same indexed object
-	// we try all posibilities of raising/lowering and keep the least one in
+	// we try all possibilities of raising/lowering and keep the least one in
 	// the sense of ex_is_less.
 	ex optimal_e = e;
 	size_t numpossibs = 1 << local_var_dummies.size();
@@ -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
@@ -872,8 +874,16 @@ contraction_done:
 					// Non-commutative products are always re-expanded to give
 					// eval_ncmul() the chance to re-order and canonicalize
 					// the product
+					bool is_a_product = (is_exactly_a<mul>(*it1) || is_exactly_a<ncmul>(*it1)) &&
+					                    (is_exactly_a<mul>(*it2) || is_exactly_a<ncmul>(*it2));
 					ex r = (non_commutative ? ex(ncmul(v, true)) : ex(mul(v)));
-					return simplify_indexed(r, free_indices, dummy_indices, sp);
+
+					// If new expression is a product we can call this function again,
+					// otherwise we need to pass argument to simplify_indexed() to be expanded
+					if (is_a_product)
+						return simplify_indexed_product(r, free_indices, dummy_indices, sp);
+					else
+						return simplify_indexed(r, free_indices, dummy_indices, sp);
 				}
 
 				// Both objects may have new indices now or they might
@@ -882,6 +892,11 @@ 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 +950,22 @@ 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
@@ -971,7 +988,7 @@ public:
 	terminfo(const ex & orig_, const ex & symm_) : orig(orig_), symm(symm_) {}
 
 	ex orig; /**< original term */
-	ex symm; /**< symmtrized term */
+	ex symm; /**< symmetrized term */
 };
 
 class terminfo_is_less {