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add numerical recipes library

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yenru0
2025-09-12 18:55:25 +09:00
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lib/nr/ansi/examples/xtqli.c Normal file
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/* Driver for routine tqli */
#include <stdio.h>
#include <math.h>
#define NRANSI
#include "nr.h"
#include "nrutil.h"
#define NP 10
#define TINY 1.0e-6
int main(void)
{
int i,j,k;
float *d,*e,*f,**a;
static float c[NP][NP]={
5.0, 4.3, 3.0, 2.0, 1.0, 0.0,-1.0,-2.0,-3.0,-4.0,
4.3, 5.1, 4.0, 3.0, 2.0, 1.0, 0.0,-1.0,-2.0,-3.0,
3.0, 4.0, 5.0, 4.0, 3.0, 2.0, 1.0, 0.0,-1.0,-2.0,
2.0, 3.0, 4.0, 5.0, 4.0, 3.0, 2.0, 1.0, 0.0,-1.0,
1.0, 2.0, 3.0, 4.0, 5.0, 4.0, 3.0, 2.0, 1.0, 0.0,
0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 4.0, 3.0, 2.0, 1.0,
-1.0, 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 4.0, 3.0, 2.0,
-2.0,-1.0, 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 4.0, 3.0,
-3.0,-2.0,-1.0, 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 4.0,
-4.0,-3.0,-2.0,-1.0, 0.0, 1.0, 2.0, 3.0, 4.0, 5.0};
d=vector(1,NP);
e=vector(1,NP);
f=vector(1,NP);
a=matrix(1,NP,1,NP);
for (i=1;i<=NP;i++)
for (j=1;j<=NP;j++) a[i][j]=c[i-1][j-1];
tred2(a,NP,d,e);
tqli(d,e,NP,a);
printf("\nEigenvectors for a real symmetric matrix\n");
for (i=1;i<=NP;i++) {
for (j=1;j<=NP;j++) {
f[j]=0.0;
for (k=1;k<=NP;k++)
f[j] += (c[j-1][k-1]*a[k][i]);
}
printf("%s %3d %s %10.6f\n","eigenvalue",i," =",d[i]);
printf("%11s %14s %9s\n","vector","mtrx*vect.","ratio");
for (j=1;j<=NP;j++) {
if (fabs(a[j][i]) < TINY)
printf("%12.6f %12.6f %12s\n",
a[j][i],f[j],"div. by 0");
else
printf("%12.6f %12.6f %12.6f\n",
a[j][i],f[j],f[j]/a[j][i]);
}
printf("Press ENTER to continue...\n");
(void) getchar();
}
free_matrix(a,1,NP,1,NP);
free_vector(f,1,NP);
free_vector(e,1,NP);
free_vector(d,1,NP);
return 0;
}
#undef NRANSI