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#include <stdio.h>
#include <math.h>
#define N 10
#define NUM_X 5
int main() {
int i,nfunc;
array double f[NUM_X],x[NUM_X],y[NUM_X];
array float xa[N],ya[N];
/* Generation of interpolation tables of sin(x) function */
linspace(xa, 0, M_PI);
ya = sin(xa);
linspace(x, 0.15, M_PI-0.15);
f=sin(x);
/*Spline interpolation */
printf("\nCubic spline interpolation of function sin(x)\n");
printf("\n%9s %13s %17s\n","x","f(x)","interpolation");
interp1(y, x, xa, ya, "spline");
for(i=0;i<NUM_X;i++)
printf("%12.6f %12.6f %12.6f\n",x[i],f[i],y[i]);
/*Linear interpolation */
printf("\nLinear interpolation of function sin(x)\n");
printf("\n%9s %13s %17s\n","x","f(x)","interpolation");
interp1(y, x, xa, ya, "linear");
for(i=0;i<NUM_X;i++)
printf("%12.6f %12.6f %12.6f\n",x[i],f[i],y[i]);
}
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Cubic spline interpolation of function sin(x)
x f(x) interpolation
0.150000 0.149438 0.149431
0.860398 0.758102 0.758072
1.570796 1.000000 0.999960
2.281194 0.758102 0.758072
2.991593 0.149438 0.149431
Linear interpolation of function sin(x)
x f(x) interpolation
0.150000 0.149438 0.146972
0.860398 0.758102 0.746562
1.570796 1.000000 0.984808
2.281194 0.758102 0.746562
2.991593 0.149438 0.146972
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