43 lines
832 B
C
43 lines
832 B
C
|
|
/* Driver for routine pcshft */
|
|
|
|
#include <stdio.h>
|
|
#include <math.h>
|
|
#define NRANSI
|
|
#include "nr.h"
|
|
|
|
#define NVAL 40
|
|
#define PIO2 1.5707963
|
|
|
|
float func(float x)
|
|
{
|
|
return x*x*(x*x-2.0)*sin(x);
|
|
}
|
|
|
|
int main(void)
|
|
{
|
|
int i,j,mval;
|
|
float a=(-PIO2),b=PIO2,poly,x;
|
|
float c[NVAL],d[NVAL];
|
|
|
|
chebft(a,b,c,NVAL,func);
|
|
for (;;) {
|
|
printf("\nHow many terms in Chebyshev evaluation?\n");
|
|
printf("Enter n between 6 and %2d. (n=0 to end).\n",NVAL);
|
|
scanf("%d",&mval);
|
|
if ((mval <= 0) || (mval > NVAL)) break;
|
|
chebpc(c,d,mval);
|
|
pcshft(a,b,d,mval);
|
|
/* Test shifted polynomial */
|
|
printf("\n%9s %14s %14s\n","x","actual","polynomial");
|
|
for (i = -8;i<=8;i++) {
|
|
x=i*PIO2/10.0;
|
|
poly=d[mval-1];
|
|
for (j=mval-2;j>=0;j--) poly=poly*x+d[j];
|
|
printf("%12.6f %12.6f %12.6f\n",x,func(x),poly);
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
#undef NRANSI
|