Update copyright statements.

[ginac.git] / check / match_bug.cpp

diff --git a/check/match_bug.cpp b/check/match_bug.cpp
index 70e55420a0e7f3f0c058daddac440533d1f29a00..a0ade413cf2cffe18cc2058ead664f8675fc7b2e 100644 (file)
--- a/check/match_bug.cpp
+++ b/check/match_bug.cpp
@@ -1,11 +1,29 @@
-/**
- * @file match_bug.cpp
+/** @file match_bug.cpp
  *
- * Check for bug in GiNaC::ex::match() described here:
- * http://www.ginac.de/pipermail/ginac-devel/2006-April/000942.html
+ *  Check for bug in GiNaC::ex::match() described here:
+ *  http://www.ginac.de/pipermail/ginac-devel/2006-April/000942.html */
+
+/*
+ *  GiNaC Copyright (C) 1999-2014 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
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
+
 #include "ginac.h"
 #include "error_report.h"
+
 #include <iostream>
 using namespace GiNaC;
 
@@ -27,8 +45,8 @@ static void failed_match_have_side_effects()
        // obviously e does NOT match the pattern
        exmap repls;
        bool match_p = e.match(pattern, repls);
-       bug_on(match_p, "match(" << e << ", " << pattern << ") says \"Yes\"");
-       bug_on(repls.size() != 0,
+       cbug_on(match_p, "match(" << e << ", " << pattern << ") says \"Yes\"");
+       cbug_on(repls.size() != 0,
                "failed match have side effects: repls = " << repls);
 }
 
@@ -51,16 +69,59 @@ static void match_false_negative()
        ex pattern = pow(wild(0), -1)*pow(x, wild(2));
        exmap repls;
        bool match_p = e.match(pattern, repls);
-       bug_on(!match_p, "false negative: " << e << " did not match "
+       cbug_on(!match_p, "false negative: " << e << " did not match "
                        << pattern);
 }
 
+/*
+ * expairseq::match() should not have any side effects if the match failed.
+ */
+static void expairseq_failed_match_no_side_effect(int count)
+{
+       for (int i = 0; i < count; ++i) {
+               exmap repls;
+               symbol t("t"), A("A");
+               ex e = pow(t, 2)*exp(t*A);
+               ex pattern = pow(t, wild(0))*exp(wild(1))*A;
+               bool matched = e.match(pattern, repls);
+               cbug_on(matched, "unexpected match: " << e << " vs " << pattern);
+               cbug_on(repls.size(), "failed match has side effects");
+       }
+}
+
+/*
+ * exp(a)*sin(x) + exp(b)*sin(y) used to fail to match
+ * exp(a)*sin($0) + exp(b)*sin($1). The failure was not deterministic.
+ *
+ * The first attempted submatch is sin(y)*exp(b) with sin($0)*exp(a).
+ * It fails but $0 == y gets assigned due to a spurious side effect.
+ * Next submatch is sin(x)*exp(a) with sin($0)*exp(a) (the same pattern
+ * as in the first submatch). This one fails because of (incorrect)
+ * $0 == y assignment.
+ *
+ * Note: due to the unstable term ordering the sequence of submatches
+ * might be different and the match might succeed (as it should), hence
+ * we repeat the test several times.
+ */
+static void expairseq_match_false_negative(int count)
+{
+       for (int i = 0; i < count; ++i) {
+               symbol a("a"), b("b"), x("x"), y("y");
+               ex e = exp(a)*sin(x) + exp(b)*sin(y);
+               ex pattern = exp(a)*sin(wild(0)) + exp(b)*sin(wild(1));
+               cbug_on(!e.match(pattern), "match failed: " << e << "did not"
+                       "match " << pattern);
+       }
+}
+
 int main(int argc, char** argv)
 {
+       const int repetitions = 100;
        std::cout << "checking for historical bugs in match()... " << std::flush;
        failed_match_have_side_effects();
        match_false_negative();
+       expairseq_failed_match_no_side_effect(repetitions);
+       expairseq_match_false_negative(repetitions);
        std::cout << "not found. ";
        return 0;
 }
-