/* nag_enum_name_to_value (x04nac) Example Program.
 *
 * Copyright 2021 Numerical Algorithms Group.
 *
 * Mark 27.3, 2021.
 */

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

int main(void) {
  /* Scalars */
  Integer i, j, n, nrhs, pda, pdb;
  Integer exit_status = 0;
  NagError fail;
  Nag_OrderType order;
  Nag_TransType trans;
  Nag_MatrixType matrix;
  Nag_DiagType unitdiag;

  /* Arrays */
  double *a = 0, *b = 0;
  Integer *ipiv = 0;
  char nag_enum_arg[20];

  INIT_FAIL(fail);

  printf("nag_enum_name_to_value (x04nac) Example Program Results\n\n");

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

  /* Read the problem dimensions. */
  scanf("%" NAG_IFMT "%" NAG_IFMT "%*[^\n] ", &n, &nrhs);

  /* Read the storage order of the matrices and convert to value. */
  scanf("%19s%*[^\n] ", nag_enum_arg);

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

  /* Read whether matrix A is to be transposed and convert. */
  scanf("%19s%*[^\n] ", nag_enum_arg);
  trans = (Nag_TransType)nag_enum_name_to_value(nag_enum_arg);

  /* Read and convert parameters for writing solution using
   * nag_file_print_matrix_real_gen (x04cac). */
  scanf("%19s%*[^\n] ", nag_enum_arg);
  matrix = (Nag_MatrixType)nag_enum_name_to_value(nag_enum_arg);
  scanf("%19s%*[^\n] ", nag_enum_arg);
  unitdiag = (Nag_DiagType)nag_enum_name_to_value(nag_enum_arg);

  /* Set up defines for reading matrices using given order. */
#define A(I, J) a[(J - 1) * pda + I - 1]
#define B(I, J) b[(J - 1) * pdb + I - 1]
  if (order == (int)Nag_ColMajor) {
    pda = n;
    pdb = n;
  } else {
    pda = n;
    pdb = nrhs;
  }

  /* Allocate memory */
  if (!(a = NAG_ALLOC(n * n, double)) || !(b = NAG_ALLOC(n * nrhs, double)) ||
      !(ipiv = NAG_ALLOC(n, Integer))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }

  /* Read A and B from data file */
  if (order == Nag_ColMajor) {
    for (i = 1; i <= n; ++i) {
      for (j = 1; j <= n; ++j)
        scanf("%lf", &A(i, j));
    }
    scanf("%*[^\n] ");
    for (i = 1; i <= n; ++i) {
      for (j = 1; j <= nrhs; ++j)
        scanf("%lf", &B(i, j));
    }
    scanf("%*[^\n] ");
  } else {
    for (i = 1; i <= n; ++i) {
      for (j = 1; j <= n; ++j)
        scanf("%lf", &A(j, i));
    }
    scanf("%*[^\n] ");
    for (i = 1; i <= n; ++i) {
      for (j = 1; j <= nrhs; ++j)
        scanf("%lf", &B(j, i));
    }
    scanf("%*[^\n] ");
  }

  /* Factorize A */
  /* nag_lapacklin_dgetrf (f07adc).
   * LU factorization of real m by n matrix
   */
  nag_lapacklin_dgetrf(order, n, n, a, pda, ipiv, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_lapacklin_dgetrf (f07adc).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

  /* Compute solution */
  /* nag_lapacklin_dgetrs (f07aec).
   * Solution of real system of linear equations, multiple
   * right-hand sides, matrix already factorized by nag_lapacklin_dgetrf
   * (f07adc)
   */
  nag_lapacklin_dgetrs(order, trans, n, nrhs, a, pda, ipiv, b, pdb, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_lapacklin_dgetrs (f07aec).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

  /* nag_enum_value_to_name (x04nbc).
   * Converts NAG enum member value to its name
   */
  printf("Array storage scheme used in nag_lapacklin_dgetrs (f07aec) is %s\n",
         nag_enum_value_to_name(order));

  /* nag_error_name_to_code (x04ncc).
   * Converts NAG error name to its code value
   */
  printf("nag_lapacklin_dgetrs (f07aec) returns with the error code "
         "(fail.code) set to %d\n\n",
         nag_error_name_to_code("NE_NOERROR"));

  /* Print solution */
  /* nag_file_print_matrix_real_gen (x04cac).
   * Print real general matrix (easy-to-use)
   */
  fflush(stdout);
  nag_file_print_matrix_real_gen(order, matrix, unitdiag, n, nrhs, b, pdb,
                                 "Solution(s)", 0, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_file_print_matrix_real_gen (x04cac).\n%s\n",
           fail.message);
    exit_status = 1;
    goto END;
  }
END:
  NAG_FREE(a);
  NAG_FREE(b);
  NAG_FREE(ipiv);
  return exit_status;
}