36 lines
500 B
C
36 lines
500 B
C
|
|
#include "nrutil.h"
|
|
|
|
void vander(x,w,q,n)
|
|
double q[],w[],x[];
|
|
int n;
|
|
{
|
|
int i,j,k;
|
|
double b,s,t,xx;
|
|
double *c;
|
|
|
|
c=dvector(1,n);
|
|
if (n == 1) w[1]=q[1];
|
|
else {
|
|
for (i=1;i<=n;i++) c[i]=0.0;
|
|
c[n] = -x[1];
|
|
for (i=2;i<=n;i++) {
|
|
xx = -x[i];
|
|
for (j=(n+1-i);j<=(n-1);j++) c[j] += xx*c[j+1];
|
|
c[n] += xx;
|
|
}
|
|
for (i=1;i<=n;i++) {
|
|
xx=x[i];
|
|
t=b=1.0;
|
|
s=q[n];
|
|
for (k=n;k>=2;k--) {
|
|
b=c[k]+xx*b;
|
|
s += q[k-1]*b;
|
|
t=xx*t+b;
|
|
}
|
|
w[i]=s/t;
|
|
}
|
|
}
|
|
free_dvector(c,1,n);
|
|
}
|