NAG Library Manual, Mark 30.2
Interfaces:  FL   CL   CPP   AD 

NAG CL Interface Introduction
Example description
/* nag_matop_complex_herm_matrix_exp (f01fdc) Example Program.
 *
 * Copyright 2024 Numerical Algorithms Group.
 *
 * Mark 30.2, 2024.
 */
#include <nag.h>
int main(void) {
  /* Scalars */
  char *outfile = 0;
  Integer exit_status = 0;
  Integer i, j, n, pda;

  /* Arrays */
  char uplo_c[40];
  Complex *a = 0;

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

  INIT_FAIL(fail);

  printf("nag_matop_complex_herm_matrix_exp (f01fdc) Example Program Results");
  printf("\n\n");
  fflush(stdout);

  /* Read matrix dimension and storage 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), Complex))) {
    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 , %lf ) ", &A(i, j).re, &A(i, j).im);
  } else {
    matrix = Nag_LowerMatrix;
    for (i = 1; i <= n; i++)
      for (j = 1; j <= i; j++)
        scanf(" ( %lf , %lf ) ", &A(i, j).re, &A(i, j).im);
  }
  scanf("%*[^\n]");

  /* nag_matop_complex_herm_matrix_exp (f01fdc).
   * Complex Hermitian matrix exponential
   */
  nag_matop_complex_herm_matrix_exp(order, uplo, n, a, pda, &fail);
  if (fail.code != NE_NOERROR) {
    printf("%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

  /* nag_file_print_matrix_complex_gen (x04dac).
   * Print complex general matrix (easy-to-use)
   */
  nag_file_print_matrix_complex_gen(order, matrix, Nag_NonUnitDiag, n, n, a,
                                    pda, "Hermitian Exp(A)", outfile, &fail);
  if (fail.code != NE_NOERROR) {
    printf("%s\n", fail.message);
    exit_status = 2;
    goto END;
  }

END:
  NAG_FREE(a);

  return exit_status;
}