21 lines
423 B
C++
21 lines
423 B
C++
#include "nr.h"
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void NR::tridag(Vec_I_DP &a, Vec_I_DP &b, Vec_I_DP &c, Vec_I_DP &r, Vec_O_DP &u)
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{
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int j;
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DP bet;
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int n=a.size();
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Vec_DP gam(n);
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if (b[0] == 0.0) nrerror("Error 1 in tridag");
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u[0]=r[0]/(bet=b[0]);
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for (j=1;j<n;j++) {
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gam[j]=c[j-1]/bet;
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bet=b[j]-a[j]*gam[j];
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if (bet == 0.0) nrerror("Error 2 in tridag");
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u[j]=(r[j]-a[j]*u[j-1])/bet;
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}
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for (j=(n-2);j>=0;j--)
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u[j] -= gam[j+1]*u[j+1];
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}
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