kopia lustrzana https://github.com/xdsopl/qsstv
59 wiersze
1.1 KiB
C++
59 wiersze
1.1 KiB
C++
#include <math.h>
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#define NRANSI
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#include "nrutil.h"
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#define TINY 1.0e-20;
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void ludcmp(float **a, int n, int *indx, float *d)
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{
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int i,imax=0,j,k;
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float big,dum,sum,temp;
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float *vv;
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vv=fvector(1,n);
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*d=1.0;
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for (i=1;i<=n;i++) {
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big=0.0;
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for (j=1;j<=n;j++)
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if ((temp=fabs(a[i][j])) > big) big=temp;
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if (big == 0.0) nrerror("Singular matrix in routine ludcmp");
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vv[i]=1.0/big;
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}
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for (j=1;j<=n;j++) {
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for (i=1;i<j;i++) {
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sum=a[i][j];
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for (k=1;k<i;k++) sum -= a[i][k]*a[k][j];
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a[i][j]=sum;
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}
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big=0.0;
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for (i=j;i<=n;i++) {
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sum=a[i][j];
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for (k=1;k<j;k++)
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sum -= a[i][k]*a[k][j];
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a[i][j]=sum;
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if ( (dum=vv[i]*fabs(sum)) >= big) {
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big=dum;
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imax=i;
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}
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}
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if (j != imax) {
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for (k=1;k<=n;k++) {
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dum=a[imax][k];
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a[imax][k]=a[j][k];
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a[j][k]=dum;
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}
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*d = -(*d);
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vv[imax]=vv[j];
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}
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indx[j]=imax;
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if (a[j][j] == 0.0) a[j][j]=TINY;
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if (j != n) {
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dum=1.0/(a[j][j]);
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for (i=j+1;i<=n;i++) a[i][j] *= dum;
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}
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}
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free_fvector(vv,1,n);
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}
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#undef TINY
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#undef NRANSI
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/* (C) Copr. 1986-92 Numerical Recipes Software 0!-"1. */
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