fixed a crash when constructing expressions like (dirac_ONE()+dirac_gamma5())*dirac_g...

[ginac.git] / ginac / clifford.cpp

diff --git a/ginac/clifford.cpp b/ginac/clifford.cpp
index 131a00eea909fa7ffe8988f399f244d1e19ea780..66ddc019ea5e76b0d10bfdb96d80e8718eb4c6b2 100644 (file)
--- a/ginac/clifford.cpp
+++ b/ginac/clifford.cpp
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's clifford algebra (Dirac gamma) objects. */
 
 /*
- *  GiNaC Copyright (C) 1999-2001 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2002 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
@@ -20,6 +20,9 @@
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
+#include <iostream>
+#include <stdexcept>
+
 #include "clifford.h"
 #include "ex.h"
 #include "idx.h"
@@ -32,11 +35,8 @@
 #include "mul.h"
 #include "print.h"
 #include "archive.h"
-#include "debugmsg.h"
 #include "utils.h"
 
-#include <stdexcept>
-
 namespace GiNaC {
 
 GINAC_IMPLEMENT_REGISTERED_CLASS(clifford, indexed)
@@ -45,12 +45,11 @@ GINAC_IMPLEMENT_REGISTERED_CLASS(diracgamma, tensor)
 GINAC_IMPLEMENT_REGISTERED_CLASS(diracgamma5, tensor)
 
 //////////
-// default constructor, destructor, copy constructor assignment operator and helpers
+// default ctor, dtor, copy ctor, assignment operator and helpers
 //////////
 
 clifford::clifford() : representation_label(0)
 {
-       debugmsg("clifford default constructor", LOGLEVEL_CONSTRUCT);
        tinfo_key = TINFO_clifford;
 }
 
@@ -74,7 +73,6 @@ DEFAULT_CTORS(diracgamma5)
  *  @see dirac_ONE */
 clifford::clifford(const ex & b, unsigned char rl) : inherited(b), representation_label(rl)
 {
-       debugmsg("clifford constructor from ex", LOGLEVEL_CONSTRUCT);
        tinfo_key = TINFO_clifford;
 }
 
@@ -83,20 +81,17 @@ clifford::clifford(const ex & b, unsigned char rl) : inherited(b), representatio
  *  @see dirac_gamma */
 clifford::clifford(const ex & b, const ex & mu, unsigned char rl) : inherited(b, mu), representation_label(rl)
 {
-       debugmsg("clifford constructor from ex,ex", LOGLEVEL_CONSTRUCT);
        GINAC_ASSERT(is_a<varidx>(mu));
        tinfo_key = TINFO_clifford;
 }
 
 clifford::clifford(unsigned char rl, const exvector & v, bool discardable) : inherited(sy_none(), v, discardable), representation_label(rl)
 {
-       debugmsg("clifford constructor from unsigned char,exvector", LOGLEVEL_CONSTRUCT);
        tinfo_key = TINFO_clifford;
 }
 
 clifford::clifford(unsigned char rl, exvector * vp) : inherited(sy_none(), vp), representation_label(rl)
 {
-       debugmsg("clifford constructor from unsigned char,exvector *", LOGLEVEL_CONSTRUCT);
        tinfo_key = TINFO_clifford;
 }
 
@@ -106,7 +101,6 @@ clifford::clifford(unsigned char rl, exvector * vp) : inherited(sy_none(), vp),
 
 clifford::clifford(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
 {
-       debugmsg("clifford constructor from archive_node", LOGLEVEL_CONSTRUCT);
        unsigned rl;
        n.find_unsigned("label", rl);
        representation_label = rl;
@@ -311,12 +305,6 @@ ex clifford::simplify_ncmul(const exvector & v) const
                }
        }
 
-       // Remove squares of gamma5
-       while (s.size() >= 2 && is_a<clifford>(s[0]) && is_a<clifford>(s[1]) && is_a<diracgamma5>(s[0].op(0)) && is_a<diracgamma5>(s[1].op(0))) {
-               s.erase(s.begin(), s.begin() + 2);
-               something_changed = true;
-       }
-
        // Remove equal adjacent gammas
        if (s.size() >= 2) {
                exvector::iterator it, itend = s.end() - 1;
@@ -325,7 +313,9 @@ ex clifford::simplify_ncmul(const exvector & v) const
                        ex & b = it[1];
                        if (!is_a<clifford>(a) || !is_a<clifford>(b))
                                continue;
-                       if (is_a<diracgamma>(a.op(0)) && is_a<diracgamma>(b.op(0))) {
+                       bool a_is_diracgamma = is_a<diracgamma>(a.op(0));
+                       bool b_is_diracgamma = is_a<diracgamma>(b.op(0));
+                       if (a_is_diracgamma && b_is_diracgamma) {
                                const ex & ia = a.op(1);
                                const ex & ib = b.op(1);
                                if (ia.is_equal(ib)) { // gamma~alpha gamma~alpha -> g~alpha~alpha
@@ -333,7 +323,12 @@ ex clifford::simplify_ncmul(const exvector & v) const
                                        b = dirac_ONE(representation_label);
                                        something_changed = true;
                                }
-                       } else if (!is_a<diracgamma>(a.op(0)) && !is_a<diracgamma>(b.op(0))) {
+                       } else if (is_a<diracgamma5>(a.op(0)) && is_a<diracgamma5>(b.op(0))) {
+                               // Remove squares of gamma5
+                               a = dirac_ONE(representation_label);
+                               b = dirac_ONE(representation_label);
+                               something_changed = true;
+                       } else if (!a_is_diracgamma && !b_is_diracgamma) {
                                const ex & ba = a.op(0);
                                const ex & bb = b.op(0);
                                if (ba.is_equal(bb)) { // a\ a\ -> a^2