/* nag_linsys_complex_posdef_packed_solve (f04cec) Example Program.
 *
 * Copyright 2019 Numerical Algorithms Group.
 *
 * Mark 27.0, 2019.
 */

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

int main(void)
{

  /* Scalars */
  double errbnd, rcond;
  Integer exit_status, i, j, n, nrhs, pdb;

  /* Arrays */
  char nag_enum_arg[40];
  char *clabs = 0, *rlabs = 0;
  Complex *ap = 0, *b = 0;

  /* Nag types */
  Nag_OrderType order;
  Nag_UploType uplo;
  NagError fail;

#ifdef NAG_COLUMN_MAJOR
#define A_UPPER(I, J) ap[J*(J-1)/2 + I - 1]
#define A_LOWER(I, J) ap[(2*n-J)*(J-1)/2 + I - 1]
#define B(I, J)       b[(J-1)*pdb + I - 1]
  order = Nag_ColMajor;
#else
#define A_LOWER(I, J) ap[I*(I-1)/2 + J - 1]
#define A_UPPER(I, J) ap[(2*n-I)*(I-1)/2 + J - 1]
#define B(I, J)       b[(I-1)*pdb + J - 1]
  order = Nag_RowMajor;
#endif

  exit_status = 0;
  INIT_FAIL(fail);

  printf("nag_linsys_complex_posdef_packed_solve (f04cec) Example Program"
         " Results\n\n");

  /* Skip heading in data file */
  scanf("%*[^\n] ");
  scanf("%" NAG_IFMT "%" NAG_IFMT "%*[^\n] ", &n, &nrhs);
  if (n > 0 && nrhs > 0) {
    /* Allocate memory */
    if (!(clabs = NAG_ALLOC(2, char)) ||
        !(rlabs = NAG_ALLOC(2, char)) ||
        !(ap = NAG_ALLOC(n * (n + 1) / 2, Complex)) ||
        !(b = NAG_ALLOC(n * nrhs, Complex)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
#ifdef NAG_COLUMN_MAJOR
    pdb = n;
#else
    pdb = nrhs;
#endif
  }
  else {
    printf("%s\n", "n and/or nrhs too small");
    exit_status = 1;
    return exit_status;
  }
  scanf("%39s%*[^\n] ", nag_enum_arg);
  /* nag_enum_name_to_value (x04nac).
   * Converts NAG enum member name to value
   */
  uplo = (Nag_UploType) nag_enum_name_to_value(nag_enum_arg);

  /* Read the upper or lower triangular part of the matrix A from */
  /* data file */

  if (uplo == Nag_Upper) {
    for (i = 1; i <= n; ++i) {
      for (j = i; j <= n; ++j) {
        scanf(" ( %lf , %lf )", &A_UPPER(i, j).re, &A_UPPER(i, j).im);
      }
    }
    scanf("%*[^\n] ");
  }
  else {
    for (i = 1; i <= n; ++i) {
      for (j = 1; j <= i; ++j) {
        scanf(" ( %lf , %lf )", &A_LOWER(i, j).re, &A_LOWER(i, j).im);
      }
    }
    scanf("%*[^\n] ");
  }

  /* Read B from data file */
  for (i = 1; i <= n; ++i) {
    for (j = 1; j <= nrhs; ++j) {
      scanf(" ( %lf , %lf )", &B(i, j).re, &B(i, j).im);
    }
  }
  scanf("%*[^\n] ");

  /* Solve the equations AX = B for X */
  /* nag_linsys_complex_posdef_packed_solve (f04cec).
   * Computes the solution and error-bound to a complex
   * Hermitian positive-definite system of linear equations,
   * packed storage
   */
  nag_linsys_complex_posdef_packed_solve(order, uplo, n, nrhs, ap, b, pdb,
                                   &rcond, &errbnd, &fail);
  if (fail.code == NE_NOERROR) {
    /* Print solution, estimate of condition number and approximate */
    /* error bound */

    /* nag_file_print_matrix_complex_gen_comp (x04dbc).
     * Print complex general matrix (comprehensive)
     */
    fflush(stdout);
    nag_file_print_matrix_complex_gen_comp(order, Nag_GeneralMatrix, Nag_NonUnitDiag,
                                  n, nrhs, b, pdb, Nag_BracketForm, "%7.4f",
                                  "Solution", Nag_IntegerLabels, 0,
                                  Nag_IntegerLabels, 0, 80, 0, 0, &fail);
    if (fail.code != NE_NOERROR) {
      printf("Error from nag_file_print_matrix_complex_gen_comp (x04dbc).\n%s\n",
             fail.message);
      exit_status = 1;
      goto END;
    }
    printf("\n");
    printf("%s\n%4s%10.1e\n", "Estimate of condition number", "",
           1.0 / rcond);
    printf("\n\n");
    printf("%s\n%4s%10.1e\n\n",
           "Estimate of error bound for computed solutions", "", errbnd);
  }
  else if (fail.code == NE_RCOND) {
    /* Matrix A is numerically singular.  Print estimate of */
    /* reciprocal of condition number and solution */

    printf("\n");
    printf("%s\n%4s%10.1e\n\n\n",
           "Estimate of reciprocal of condition number", "", rcond);
    /* nag_file_print_matrix_complex_gen_comp (x04dbc), see above. */
    fflush(stdout);
    nag_file_print_matrix_complex_gen_comp(order, Nag_GeneralMatrix, Nag_NonUnitDiag,
                                  n, nrhs, b, pdb, Nag_BracketForm, "%7.4f",
                                  "Solution", Nag_IntegerLabels, 0,
                                  Nag_IntegerLabels, 0, 80, 0, 0, &fail);
    if (fail.code != NE_NOERROR) {
      printf("Error from nag_file_print_matrix_complex_gen_comp (x04dbc).\n%s\n",
             fail.message);
      exit_status = 1;
      goto END;
    }
  }
  else if (fail.code == NE_POS_DEF) {
    /* The matrix A is not positive definite to working precision */
    printf("%s%3" NAG_IFMT "%s\n\n", "The leading minor of order ",
           fail.errnum, " is not positive definite");
  }
  else {
    printf("Error from nag_linsys_complex_posdef_packed_solve (f04cec).\n%s\n",
           fail.message);
    exit_status = 1;
    goto END;
  }
END:
  NAG_FREE(clabs);
  NAG_FREE(rlabs);
  NAG_FREE(ap);
  NAG_FREE(b);

  return exit_status;
}