/* nag_matop_real_symm_matrix_fun (f01efc) Example Program.
 *
 * Copyright 2024 Numerical Algorithms Group.
 *
 * Mark 30.3, 2024.
 */
#include <math.h>
#include <nag.h>

#ifdef __cplusplus
extern "C" {
#endif
static void NAG_CALL f(Integer *flag, Integer n, const double x[], double fx[],
                       Nag_Comm *comm);
#ifdef __cplusplus
}
#endif

int main(void) {
  /* Scalars */
  Integer exit_status = 0;
  double k = 1.0;
  Integer i, flag, j, n, pda;

  /* Arrays */
  char uplo_c[40];
  Integer iuser[1];
  double user[1];
  double *a = 0;
  char *outfile = 0;

  /* NAG types */
  Nag_UploType uplo;
  Nag_MatrixType matrix;
  Nag_Comm comm;
  Nag_OrderType order;
  NagError fail;

  INIT_FAIL(fail);

  /* Communicate constant k and initialize function counter through comm */
  comm.user = user;
  comm.iuser = iuser;
  user[0] = k;
  iuser[0] = 0;

  printf("nag_matop_real_symm_matrix_fun (f01efc) Example Program Results");
  printf("\n\n");
  fflush(stdout);

  /* Read problem parameters from data file */
  scanf("%*[^\n]%" NAG_IFMT "%*[^\n] %39s%*[^\n] ", &n, uplo_c);

  /* nag_enum_name_to_value (x04nac).
   * Converts NAG enum member name to value
   */
  uplo = (Nag_UploType)nag_enum_name_to_value(uplo_c);

  pda = n;
  if (!(a = NAG_ALLOC((pda) * (n), double))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }

#ifdef NAG_COLUMN_MAJOR
#define A(I, J) a[(J - 1) * pda + I - 1]
  order = Nag_ColMajor;
#else
#define A(I, J) a[(I - 1) * pda + J - 1]
  order = Nag_RowMajor;
#endif

  /* Read A from data file */
  if (uplo == Nag_Upper) {
    matrix = Nag_UpperMatrix;
    for (i = 1; i <= n; i++)
      for (j = i; j <= n; j++)
        scanf("%lf", &A(i, j));
  } else {
    matrix = Nag_LowerMatrix;
    for (i = 1; i <= n; i++)
      for (j = 1; j <= i; j++)
        scanf("%lf", &A(i, j));
  }
  scanf("%*[^\n]");

  /* nag_matop_real_symm_matrix_fun (f01efc).
   * Function of a real symmetric matrix
   */
  nag_matop_real_symm_matrix_fun(order, uplo, n, a, pda, f, &comm, &flag,
                                 &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_matop_real_symm_matrix_fun (f01efc).\n%s\n",
           fail.message);
    exit_status = 1;
    goto END;
  }
  /* Expected number of function evaluations is n. */
  if (iuser[0] != n)
    printf("\nNumber of function evaluations = %" NAG_IFMT "\n\n", iuser[0]);

  /* nag_file_print_matrix_real_gen (x04cac).
   * Print real general matrix (easy-to-use)
   */
  nag_file_print_matrix_real_gen(order, matrix, Nag_NonUnitDiag, n, n, a, pda,
                                 "Symmetric f(A)=cos(kA)", outfile, &fail);
  if (fail.code != NE_NOERROR) {
    printf("%s\n", fail.message);
    exit_status = 2;
    goto END;
  }

END:
  NAG_FREE(a);

  return exit_status;
}

static void NAG_CALL f(Integer *flag, Integer n, const double x[], double fx[],
                       Nag_Comm *comm) {
  Integer j;
  double k;
  if (!comm->user[0]) {
    *flag = -1;
  } else {
    k = comm->user[0];

    for (j = 0; j < n; j++) {
      comm->iuser[0]++;
      fx[j] = cos(k * x[j]);
    }
  }
}