/* nag_correg_corrmat_nearest_bounded (g02abc) Example Program.
 *
 * Copyright 2024 Numerical Algorithms Group.
 *
 * Mark 30.1, 2024.
 */

#include <nag.h>

int main(void) {

  /* Scalars */
  Integer exit_status = 0;
  double alpha, errtol, nrmgrd;
  Integer feval, i, iter, j, maxit, maxits, n, pdeig, pdg, pdx;

  /* Arrays */
  char nag_enum_arg[100];
  double *eig = 0, *g = 0, *w = 0, *x = 0;

  /* Nag Types */
  Nag_OrderType order;
  Nag_NearCorr_ProbType opt;
  NagError fail;

  INIT_FAIL(fail);

#ifdef NAG_COLUMN_MAJOR
#define G(I, J) g[(J - 1) * pdg + I - 1]
  order = Nag_ColMajor;
#else
#define G(I, J) g[(I - 1) * pdg + J - 1]
  order = Nag_RowMajor;
#endif

  /* Output preamble */
  printf("nag_correg_corrmat_nearest_bounded (g02abc)");
  printf(" Example Program Results\n\n");
  fflush(stdout);

  /* Skip heading in data file */
  scanf("%*[^\n] ");
  /* Read in the problem size, opt and alpha */
  scanf("%" NAG_IFMT "", &n);
  scanf("%39s", nag_enum_arg);
  /*
   * nag_enum_name_to_value (x04nac).
   * Converts NAG enum member name to value
   */
  opt = (Nag_NearCorr_ProbType)nag_enum_name_to_value(nag_enum_arg);
  scanf("%lf%*[^\n]", &alpha);

  pdg = n;
  pdx = n;
  if (order == Nag_ColMajor)
    pdeig = 1;
  else
    pdeig = n;

  if (!(g = NAG_ALLOC((pdg) * (n), double)) || !(w = NAG_ALLOC((n), double)) ||
      !(x = NAG_ALLOC((pdx) * (n), double)) ||
      !(eig = NAG_ALLOC((n), double))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }

  /* Read in the matrix g */
  for (i = 1; i <= n; i++)
    for (j = 1; j <= n; j++)
      scanf("%lf", &G(i, j));
  scanf("%*[^\n] ");

  /* Read in the vector w */
  for (i = 0; i < n; i++)
    scanf("%lf", &w[i]);
  scanf("%*[^\n] ");

  /* Use the defaults for errtol, maxits and maxit */
  errtol = 0.0;
  maxits = 0;
  maxit = 0;

  /*
   * nag_correg_corrmat_nearest_bounded (g02abc).
   * Computes the nearest correlation matrix incorporating weights
   * and/or bounds
   */
  nag_correg_corrmat_nearest_bounded(order, g, pdg, n, opt, alpha, w, errtol,
                                     maxits, maxit, x, pdx, &iter, &feval,
                                     &nrmgrd, &fail);
  if (fail.code != NE_NOERROR) {
    printf("%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

  /*
   * nag_file_print_matrix_real_gen (x04cac).
   * Print real general matrix (easy-to-use)
   */
  nag_file_print_matrix_real_gen(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n,
                                 n, x, pdx, "Nearest Correlation Matrix x",
                                 NULL, &fail);
  if (fail.code != NE_NOERROR) {
    printf("%s\n", fail.message);
    exit_status = 1;
    goto END;
  }
  printf("\nNumber of Newton steps taken: %11" NAG_IFMT "\n", iter);
  printf("Number of function evaluations: %9" NAG_IFMT "\n\n", feval);
  printf("alpha: %37.3f \n\n", alpha);
  fflush(stdout);

  /* nag_lapackeig_dsyev (f08fac).
   * Computes all eigenvalues and, optionally, eigenvectors of a real
   * symmetric matrix
   */
  nag_lapackeig_dsyev(order, Nag_EigVals, Nag_Upper, n, x, pdx, eig, &fail);
  if (fail.code != NE_NOERROR) {
    printf("%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

  /* nag_file_print_matrix_real_gen (x04cac).
   * Print real general matrix (easy-to-use)
   */
  nag_file_print_matrix_real_gen(order, Nag_GeneralMatrix, Nag_NonUnitDiag, 1,
                                 n, eig, pdeig, "Eigenvalues of x", NULL,
                                 &fail);
  if (fail.code != NE_NOERROR) {
    printf("%s\n", fail.message);
    exit_status = 1;
  }

END:
  NAG_FREE(eig);
  NAG_FREE(g);
  NAG_FREE(w);
  NAG_FREE(x);
  return exit_status;
}