24 lines
443 B
C
24 lines
443 B
C
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#include "nrutil.h"
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void tridag(a,b,c,r,u,n)
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float a[],b[],c[],r[],u[];
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unsigned long n;
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{
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unsigned long j;
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float bet,*gam;
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gam=vector(1,n);
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if (b[1] == 0.0) nrerror("Error 1 in tridag");
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u[1]=r[1]/(bet=b[1]);
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for (j=2;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-1);j>=1;j--)
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u[j] -= gam[j+1]*u[j+1];
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free_vector(gam,1,n);
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}
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