* Use the pointers to the flyweights, not their references!

[ginac.git] / ginac / indexed.cpp

diff --git a/ginac/indexed.cpp b/ginac/indexed.cpp
index edbc730037e9f10036e8fbadea2462af57bb85f0..40a6232c1ecdcb02f5f678acd616b79d21b76138 100644 (file)
--- a/ginac/indexed.cpp
+++ b/ginac/indexed.cpp
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's indexed expressions. */
 
 /*
- *  GiNaC Copyright (C) 1999-2003 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2004 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
@@ -325,20 +325,24 @@ ex indexed::expand(unsigned options) const
 {
        GINAC_ASSERT(seq.size() > 0);
 
-       if ((options & expand_options::expand_indexed) && is_exactly_a<add>(seq[0])) {
-
-               // expand_indexed expands (a+b).i -> a.i + b.i
-               const ex & base = seq[0];
-               ex sum = _ex0;
-               for (size_t i=0; i<base.nops(); i++) {
+       if (options & expand_options::expand_indexed) {
+               ex newbase = seq[0].expand(options);
+               if (is_exactly_a<add>(newbase)) {
+                       ex sum = _ex0;
+                       for (size_t i=0; i<newbase.nops(); i++) {
+                               exvector s = seq;
+                               s[0] = newbase.op(i);
+                               sum += thiscontainer(s).expand(options);
+                       }
+                       return sum;
+               }
+               if (!are_ex_trivially_equal(newbase, seq[0])) {
                        exvector s = seq;
-                       s[0] = base.op(i);
-                       sum += thiscontainer(s).expand();
+                       s[0] = newbase;
+                       return ex_to<indexed>(thiscontainer(s)).inherited::expand(options);
                }
-               return sum;
-
-       } else
-               return inherited::expand(options);
+       }
+       return inherited::expand(options);
 }
 
 //////////