NAG Library Manual, Mark 29
```/* nag_mv_multidimscal_metric (g03fac) Example Program.
*
* Copyright 2023 Numerical Algorithms Group.
*
* Mark 29.0, 2023.
*
*/

#include <nag.h>
#include <stdio.h>

#define X(I, J) x[(I)*tdx + J]
int main(void) {
Integer exit_status = 0, i, j, n, ndim, nn, tdx;
char nag_enum_arg[40];
double *d = 0, *e = 0, *x = 0;
Nag_Eigenvalues roots;
NagError fail;

INIT_FAIL(fail);

printf("nag_mv_multidimscal_metric (g03fac) Example Program Results\n\n");

/* Skip heading in data file */
scanf("%*[^\n]");
scanf("%" NAG_IFMT "", &n);
scanf("%" NAG_IFMT "", &ndim);
scanf("%39s", nag_enum_arg);
/* nag_enum_name_to_value (x04nac).
* Converts NAG enum member name to value
*/
roots = (Nag_Eigenvalues)nag_enum_name_to_value(nag_enum_arg);

if (ndim >= 1 && n > ndim) {
if (!(d = NAG_ALLOC(n * (n - 1) / 2, double)) ||
!(e = NAG_ALLOC(n, double)) || !(x = NAG_ALLOC(n * n, double))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
tdx = n;
} else {
printf("Invalid ndim or n.\n");
exit_status = 1;
return exit_status;
}
nn = n * (n - 1) / 2;
for (i = 0; i < nn; ++i)
scanf("%lf", &d[i]);

/* nag_mv_multidimscal_metric (g03fac).
* Principal co-ordinate analysis
*/
nag_mv_multidimscal_metric(roots, n, d, ndim, x, tdx, e, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_mv_multidimscal_metric (g03fac).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
printf("\nScaled Eigenvalues\n\n");

if (roots == Nag_LargeEigVals) {
for (i = 0; i < ndim; ++i)
printf("%10.4f", e[i]);
} else {
for (i = 0; i < n; ++i)
printf("%10.4f", e[i]);
printf("\n");
}
printf("\nCo-ordinates\n\n");
for (i = 0; i < n; ++i) {
for (j = 0; j < ndim; ++j)
printf("%10.4f", X(i, j));
printf("\n");
}
END:
NAG_FREE(d);
NAG_FREE(e);
NAG_FREE(x);
return exit_status;
}
```