*/
/*
- * GiNaC Copyright (C) 1999-2000 Johannes Gutenberg University Mainz, Germany
+ * GiNaC Copyright (C) 1999-2007 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
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "times.h"
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;
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;