25 lines
400 B
C++
25 lines
400 B
C++
#include "nr.h"
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void NR::lubksb(Mat_I_DP &a, Vec_I_INT &indx, Vec_IO_DP &b)
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{
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int i,ii=0,ip,j;
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DP sum;
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int n=a.nrows();
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for (i=0;i<n;i++) {
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ip=indx[i];
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sum=b[ip];
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b[ip]=b[i];
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if (ii != 0)
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for (j=ii-1;j<i;j++) sum -= a[i][j]*b[j];
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else if (sum != 0.0)
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ii=i+1;
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b[i]=sum;
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}
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for (i=n-1;i>=0;i--) {
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sum=b[i];
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for (j=i+1;j<n;j++) sum -= a[i][j]*b[j];
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b[i]=sum/a[i][i];
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}
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}
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