NAG Library Manual, Mark 28.7
Interfaces:  FL   CL   CPP   AD 

NAG CL Interface Introduction
Example description
/* nag_mv_rot_orthomax (g03bac) Example Program.
 *
 * Copyright 2022 Numerical Algorithms Group.
 *
 * Mark 28.7, 2022.
 *
 */

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

#define R(I, J) r[(I)*tdr + J]
#define FL(I, J) fl[(I)*tdfl + J]
#define FLR(I, J) flr[(I)*tdfl + J]

int main(void) {
  Integer exit_status = 0, i, iter, j, k, maxit, nvar, tdfl, tdr;
  double acc, *fl = 0, *flr = 0, g, *r = 0;
  char nag_enum_arg[40];
  Nag_RotationLoading stand;
  NagError fail;

  INIT_FAIL(fail);

  printf("nag_mv_rot_orthomax (g03bac) Example Program Results\n\n");

  /* Skip heading in data file */
  scanf("%*[^\n]");
  scanf("%" NAG_IFMT "", &nvar);
  scanf("%" NAG_IFMT "", &k);
  scanf("%lf", &g);
  scanf("%39s", nag_enum_arg);
  scanf("%lf", &acc);
  scanf("%" NAG_IFMT "", &maxit);

  /* nag_enum_name_to_value (x04nac).
   * Converts NAG enum member name to value
   */
  stand = (Nag_RotationLoading)nag_enum_name_to_value(nag_enum_arg);

  if (k >= 2 && nvar >= k) {
    if (!(r = NAG_ALLOC(k * k, double)) ||
        !(fl = NAG_ALLOC(nvar * k, double)) ||
        !(flr = NAG_ALLOC(nvar * k, double))) {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
    tdr = k;
    tdfl = k;
  } else {
    printf("Invalid k or nvar.\n");
    exit_status = 1;
    return exit_status;
  }
  for (i = 0; i < nvar; ++i) {
    for (j = 0; j < k; ++j)
      scanf("%lf", &FL(i, j));
  }
  /* nag_mv_rot_orthomax (g03bac).
   * Orthogonal rotations for loading matrix
   */
  nag_mv_rot_orthomax(stand, g, nvar, k, fl, tdfl, flr, r, tdr, acc, maxit,
                      &iter, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_mv_rot_orthomax (g03bac).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

  printf("\n     Rotated factor loadings\n\n");
  for (i = 0; i < nvar; ++i) {
    for (j = 0; j < k; ++j)
      printf("  %8.3f", FLR(i, j));
    printf("\n");
  }
  printf("\n     Rotation matrix\n\n");
  for (i = 0; i < k; ++i) {
    for (j = 0; j < k; ++j)
      printf("  %8.3f", R(i, j));
    printf("\n");
  }

END:
  NAG_FREE(r);
  NAG_FREE(fl);
  NAG_FREE(flr);

  return exit_status;
}