Fixed log-patch.

[ginac.git] / check / time_vandermonde.cpp

diff --git a/check/time_vandermonde.cpp b/check/time_vandermonde.cpp
index 69f8934a44d66801f5839928c157d598123e7a0b..1755ed6458c51fb828d99e47da277cca3deaae38 100644 (file)
--- a/check/time_vandermonde.cpp
+++ b/check/time_vandermonde.cpp
@@ -7,7 +7,7 @@
  */
 
 /*
- *  GiNaC Copyright (C) 1999-2000 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
@@ -29,34 +29,39 @@
 static unsigned vandermonde_det(unsigned size)
 {
        unsigned result = 0;
-       symbol a("a");
-       
+       const symbol a("a");
+
        // construct Vandermonde matrix:
        matrix M(size,size);
        for (unsigned ro=0; ro<size; ++ro) {
                for (unsigned co=0; co<size; ++co) {
                        if (ro%2)
-                               M.set(ro,co,pow(-pow(a,1+ro/2),co));
+                               M(ro,co) = pow(-pow(a,1+ro/2),co);
                        else
-                               M.set(ro,co,pow(pow(a,1+ro/2),co));
+                               M(ro,co) = pow(pow(a,1+ro/2),co);
                }
        }
-       
+
        // compute determinant:
-       ex vdet = M.determinant();
-       
-       // dirty consistency check of result:
-       if (!vdet.subs(a==1).is_zero()) {
+       ex det = M.determinant();
+
+       // check the result:
+       ex vanddet = 1;
+       for (unsigned i=0; i<size; ++i)
+               for (unsigned j=0; j<i; ++j)
+                       vanddet *= M(i,1) - M(j,1);
+
+       if (expand(det - vanddet) != 0) {
                clog << "Determaint of Vandermonde matrix " << endl
-                        << "M==" << M << endl
-                        << "was miscalculated: det(M)==" << vdet << endl;
+                    << "M==" << M << endl
+                    << "was miscalculated: det(M)==" << det << endl;
                ++result;
        }
-       
+
        return result;
 }
 
-unsigned time_vandermonde(void)
+unsigned time_vandermonde()
 {
        unsigned result = 0;
        
@@ -67,10 +72,10 @@ unsigned time_vandermonde(void)
        vector<double> times;
        timer swatch;
        
-       sizes.push_back(4);
        sizes.push_back(6);
        sizes.push_back(8);
        sizes.push_back(10);
+       sizes.push_back(12);
        
        for (vector<unsigned>::iterator i=sizes.begin(); i!=sizes.end(); ++i) {
                int count = 1;