```/* nag_mv_discrim_mahal (g03dbc) Example Program.
*
* Copyright 2020 Numerical Algorithms Group.
*
* Mark 27.1, 2020.
*
*/

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

#define D(I, J) d[(I)*tdd + J]
#define X(I, J) x[(I)*tdx + J]

int main(void) {

Integer i, j, m, n, ng, nobs, nvar, tdd, tdgmean, tdx;
Integer exit_status = 0, *ing = 0, *isx = 0, *nig = 0;
char nag_enum_arg[40];
double df, sig, stat;
double *d = 0, *det = 0, *gc = 0, *gmean = 0, *wt = 0;
double *wtptr = 0, *x = 0;
Nag_GroupCovars equal;
Nag_Boolean weight;
NagError fail;

INIT_FAIL(fail);

printf("nag_mv_discrim_mahal (g03dbc) Example Program Results\n\n");

/* Skip headings in data file */
scanf("%*[^\n]");
scanf("%" NAG_IFMT "", &n);
scanf("%" NAG_IFMT "", &m);
scanf("%" NAG_IFMT "", &nvar);
scanf("%" NAG_IFMT "", &ng);
scanf("%39s", nag_enum_arg);
/* nag_enum_name_to_value (x04nac).
* Converts NAG enum member name to value
*/
weight = (Nag_Boolean)nag_enum_name_to_value(nag_enum_arg);

if (n >= 1 && nvar >= 1 && m >= nvar && ng >= 2) {
if (!(det = NAG_ALLOC(ng, double)) ||
!(gc = NAG_ALLOC((ng + 1) * nvar * (nvar + 1) / 2, double)) ||
!(gmean = NAG_ALLOC(ng * nvar, double)) ||
!(wt = NAG_ALLOC(n, double)) || !(x = NAG_ALLOC(n * m, double)) ||
!(ing = NAG_ALLOC(n, Integer)) || !(isx = NAG_ALLOC(m, Integer)) ||
!(nig = NAG_ALLOC(ng, Integer))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
tdgmean = nvar;
tdx = m;
} else {
printf("Invalid n or nvar or m or ng.\n");
exit_status = 1;
return exit_status;
}
if (weight) {
for (i = 0; i < n; ++i) {
for (j = 0; j < m; ++j)
scanf("%lf", &X(i, j));
scanf("%" NAG_IFMT "", &ing[i]);
scanf("%lf", &wt[i]);
}
wtptr = wt;
} else {
for (i = 0; i < n; ++i) {
for (j = 0; j < m; ++j)
scanf("%lf", &X(i, j));
scanf("%" NAG_IFMT "", &ing[i]);
}
}
for (j = 0; j < m; ++j)
scanf("%" NAG_IFMT "", &isx[j]);
/* nag_mv_discrim (g03dac).
* Test for equality of within-group covariance matrices
*/
nag_mv_discrim(n, m, x, tdx, isx, nvar, ing, ng, wtptr, nig, gmean, tdgmean,
det, gc, &stat, &df, &sig, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_mv_discrim (g03dac).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
scanf("%" NAG_IFMT "", &nobs);
scanf("%39s", nag_enum_arg);
equal = (Nag_GroupCovars)nag_enum_name_to_value(nag_enum_arg);
if (nobs >= 1) {
if (!(d = NAG_ALLOC(nobs * ng, double))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
tdd = ng;

for (i = 0; i < nobs; ++i) {
for (j = 0; j < m; ++j)
scanf("%lf", &X(i, j));
}

/* nag_mv_discrim_mahal (g03dbc).
* Mahalanobis squared distances, following nag_mv_discrim
* (g03dac)
*/
nag_mv_discrim_mahal(equal, Nag_SamplePoints, nvar, ng, gmean, tdgmean, gc,
nobs, m, isx, x, tdx, d, tdd, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_mv_discrim_mahal (g03dbc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
printf("\n   Obs          Distances\n\n");
for (i = 0; i < nobs; ++i) {
printf(" %3" NAG_IFMT "", i + 1);
for (j = 0; j < ng; ++j)
printf("%10.3f", D(i, j));
printf("\n");
}
}

END:
NAG_FREE(d);
NAG_FREE(det);
NAG_FREE(gc);
NAG_FREE(gmean);
NAG_FREE(wt);
NAG_FREE(x);
NAG_FREE(ing);
NAG_FREE(isx);
NAG_FREE(nig);

return exit_status;
}
```