- collect_common_factors() works better with negative powers

[ginac.git] / check / check_numeric.cpp

diff --git a/check/check_numeric.cpp b/check/check_numeric.cpp
index 3c569357f8c456210d52eee75ca6a8229ef56fad..34c183526777856b6af9cb543fc8a20a0d7a8e6c 100644 (file)
--- a/check/check_numeric.cpp
+++ b/check/check_numeric.cpp
@@ -4,7 +4,7 @@
  *  tests on these numbers like is_integer() etc... */
 
 /*
- *  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
@@ -60,28 +60,38 @@ static unsigned check_numeric2(void)
        int i_num, i_den;
        
        // Check non-nested radicals (n/d)^(m/n) in ex wrapper class:
-       for (int i=0; i<200; ++i) {  // FIXME: run to ~200
+       for (int i=0; i<200; ++i) {
                for (int j=2; j<13; ++j) {
                        // construct an exponent 1/j...
                        numeric nm(1,j);
                        nm += numeric(int(20.0*rand()/(RAND_MAX+1.0))-10);
                        // ...a numerator...
-                       do { i_num = rand(); } while (i_num == 0);
+                       do {
+                               i_num = rand();
+                       } while (i_num<=0);
                        numeric num(i_num);
                        // ...and a denominator.
-                       do { i_den = (rand())/100; } while (i_den == 0);
+                       do {
+                               i_den = (rand())/100;
+                       } while (i_den<=0);
                        numeric den(i_den);
                        // construct the radicals:
                        ex radical = pow(ex(num)/ex(den),ex(nm));
                        numeric floating = pow(num/den,nm);
                        // test the result:
                        if (is_a<numeric>(radical)) {
-                               clog << "(" << num << "/" << den << ")^(" << nm
-                                    << ") should have been a product, instead it's "
-                                    << radical << endl;
-                               errorflag = true;
+                               // This is very improbable with decent random numbers but it
+                               // still can happen, so we better check if it is correct:
+                               if (pow(radical,inverse(nm))==num/den) {
+                                       // Aha! We drew some lucky numbers. Nothing to see here...
+                               } else {
+                                       clog << "(" << num << "/" << den << ")^(" << nm
+                                                << ") should have been a product, instead it's "
+                                                << radical << endl;
+                                       errorflag = true;
+                               }
                        }
-                       numeric ratio = ex_to<numeric>(evalf(radical))/floating;
+                       numeric ratio = abs(ex_to<numeric>(evalf(radical))/floating);
                        if (ratio>1.0001 && ratio<0.9999) {
                                clog << "(" << num << "/" << den << ")^(" << nm
                                     << ") erroneously evaluated to " << radical;