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