/* nag_dspsv (f07pac) Example Program.
 *
 * Copyright 2014 Numerical Algorithms Group.
 *
 * Mark 23, 2011.
 */

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagf07.h>

int main(void)
{

  /* Scalars */
  Integer       exit_status = 0, i, j, n, nrhs, pdb;

  /* Arrays */
  double        *ap = 0, *b = 0;
  Integer       *ipiv = 0;
  char          nag_enum_arg[40];

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

#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

  INIT_FAIL(fail);

  printf("nag_dspsv (f07pac) Example Program Results\n\n");

  /* Skip heading in data file */
  scanf("%*[^\n]");
  scanf("%ld%ld%*[^\n]", &n, &nrhs);
  if (n < 0 || nrhs < 0)
    {
      printf("Invalid n or nrhs\n");
      exit_status = 1;
      goto END;
    }
  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);

  /* Allocate memory */
  if (!(ap = NAG_ALLOC(n*(n+1)/2, double)) ||
      !(b = NAG_ALLOC(n*nrhs, double)) ||
      !(ipiv = NAG_ALLOC(n, Integer)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

#ifdef NAG_COLUMN_MAJOR
  pdb = n;
#else
  pdb = nrhs;
#endif

  /* Read the 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", &A_UPPER(i, j));
  else
    for (i = 1; i <= n; ++i)
      for (j = 1; j <= i; ++j) scanf("%lf", &A_LOWER(i, j));
  scanf("%*[^\n]");

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

  /* Solve the equations Ax = b for x using nag_dspsv (f07pac). */
  nag_dspsv(order, uplo, n, nrhs, ap, ipiv, b, pdb, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_dspsv (f07pac).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print solution */
  printf("   Solution\n");
  for (i = 1; i <= n; ++i)
    {
      for (j = 1; j <= nrhs; ++j)
        printf(" %10.4f%s", B(i, j), j%7 == 0?"\n":"");
      printf("\n");
    }

 END:
  NAG_FREE(ap);
  NAG_FREE(b);
  NAG_FREE(ipiv);

  return exit_status;
}
#undef A_UPPER
#undef A_LOWER
#undef B