NAG Library Manual, Mark 27.3
```/* nag_interp_dimn_scat_shep (e01zmc) Example Program.
*
* Copyright 2021 Numerical Algorithms Group.
*
* Mark 27.3, 2021.
*/
#include <math.h>
#include <nag.h>

int main(void) {
/* Scalars */
Integer exit_status = 0;
Integer d, i, j, liq, lrq, m, n, nq, nw;
/* Arrays */
double *f = 0, *q = 0, *qx = 0, *rq = 0, *x = 0, *xe = 0;
Integer *iq = 0;
/* NAG types */
NagError fail;

INIT_FAIL(fail);

printf("nag_interp_dimn_scat_shep (e01zmc) Example Program Results\n");

/* Skip heading in data file */
scanf("%*[^\n] ");

/* Input the number of nodes. */
scanf("%" NAG_IFMT " %" NAG_IFMT "%*[^\n] ", &d, &m);

liq = 2 * m + 1;
lrq = (d + 1) * (d + 2) / 2 * m + 2 * d + 1;
if (!(x = NAG_ALLOC(d * m, double)) || !(f = NAG_ALLOC(m, double)) ||
!(iq = NAG_ALLOC(liq, Integer)) || !(rq = NAG_ALLOC(lrq, double))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Input the data points X and F. */
for (i = 0; i < m; i++) {
for (j = 0; j < d; j++)
scanf("%lf", &x[i * d + j]);
scanf("%lf%*[^\n] ", &f[i]);
}

/* Generate the interpolant using nag_interp_dimn_scat_shep (e01zmc):
Interpolating functions, modified Shepard's method, d variables. */
nq = 0;
nw = 0;
nag_interp_dimn_scat_shep(d, m, x, f, nw, nq, iq, rq, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_interp_dimn_scat_shep (e01zmc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

/* Input the number of evaluation points and allocate arrays with lengths
based on this. */
scanf("%" NAG_IFMT "%*[^\n]", &n);
if (!(xe = NAG_ALLOC((d) * (n), double)) || !(q = NAG_ALLOC((n), double)) ||
!(qx = NAG_ALLOC((d) * (n), double))) {
printf("Allocation failure\n");
exit_status = -2;
goto END;
}

/* Input the evaluation points. */
for (i = 0; i < n; i++) {
for (j = 0; j < d; j++)
scanf("%lf", &xe[i * d + j]);
scanf("%*[^\n] ");
}
/* Evaluate the interpolant using nag_interp_dimn_scat_shep_eval (e01znc), at
* given interpolated values, where interpolant previously computed by
* nag_interp_dimn_scat_shep (e01zmc). */
nag_interp_dimn_scat_shep_eval(d, m, x, f, iq, rq, n, xe, q, qx, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_interp_dimn_scat_shep_eval (e01znc).\n%s\n",
fail.message);
exit_status = 2;
goto END;
}

/* Print evaluation points and interpolated function values at those points */

printf("\n%4s|%39s%23s|%8s", "", "Interpolated Evaluation Points", "",
"Values\n");
printf(" ---|--------------------------------------------------------------");
printf("+-------\n");
printf(" i  |  ");
for (i = 0; i < d; i++)
printf("XE(%1" NAG_IFMT ",i)   ", i);
printf("|  q[i]\n");
printf(" ---|--------------------------------------------------------------");
printf("--------\n");

/* Results */
for (i = 0; i < n; i++) {
printf(" %1" NAG_IFMT " ", i);
for (j = 0; j < d; j++)
printf("%10.4f", xe[i * d + j]);
printf("  %10.4f\n", q[i]);
}

END:
NAG_FREE(f);
NAG_FREE(q);
NAG_FREE(qx);
NAG_FREE(rq);
NAG_FREE(x);
NAG_FREE(xe);
NAG_FREE(iq);

return exit_status;
}
```