25 lines
558 B
C++
25 lines
558 B
C++
#include <cmath>
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#include "nr.h"
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using namespace std;
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void NR::qrupdt(Mat_IO_DP &r, Mat_IO_DP &qt, Vec_IO_DP &u, Vec_I_DP &v)
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{
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int i,k;
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int n=u.size();
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for (k=n-1;k>=0;k--)
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if (u[k] != 0.0) break;
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if (k < 0) k=0;
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for (i=k-1;i>=0;i--) {
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rotate(r,qt,i,u[i],-u[i+1]);
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if (u[i] == 0.0)
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u[i]=fabs(u[i+1]);
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else if (fabs(u[i]) > fabs(u[i+1]))
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u[i]=fabs(u[i])*sqrt(1.0+SQR(u[i+1]/u[i]));
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else u[i]=fabs(u[i+1])*sqrt(1.0+SQR(u[i]/u[i+1]));
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}
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for (i=0;i<n;i++) r[0][i] += u[0]*v[i];
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for (i=0;i<k;i++)
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rotate(r,qt,i,r[i][i],-r[i+1][i]);
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}
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