* Hahaha! The second of the two tests was actually BS(tm) but this was only
authorRichard Kreckel <Richard.Kreckel@uni-mainz.de>
Sun, 28 Oct 2001 17:37:50 +0000 (17:37 +0000)
committerRichard Kreckel <Richard.Kreckel@uni-mainz.de>
Sun, 28 Oct 2001 17:37:50 +0000 (17:37 +0000)
  triggered with nonvanishing probability on systems like IRIX with a weak
  rand() function.  Added a little additional check to trap those cases.

check/check_numeric.cpp

index 74dcf33..ef5d7c3 100644 (file)
@@ -66,20 +66,30 @@ static unsigned check_numeric2(void)
                        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 = abs(ex_to<numeric>(evalf(radical))/floating);
                        if (ratio>1.0001 && ratio<0.9999) {