/* nag_zgbsvx (f07bpc) Example Program.
 *
 * Copyright 2004 Numerical Algorithms Group.
 *
 * Mark 23, 2011.
 */

#include <stdio.h>
#include <nag.h>
#include <nagx04.h>
#include <nag_stdlib.h>
#include <nagf07.h>

int main(void)
{

  /* Scalars */
  double                growth_factor, rcond;
  Integer               exit_status = 0, i, j, kl, ku, n, nrhs, pdab, pdafb,
                        pdb, pdx;

  /* Arrays */
  Complex               *ab = 0, *afb = 0, *b = 0, *x = 0;
  double                *berr = 0, *c = 0, *ferr = 0, *r = 0;
  Integer               *ipiv = 0;

  /* Nag Types */
  NagError      fail;
  Nag_OrderType         order;
  Nag_EquilibrationType equed;

#ifdef NAG_COLUMN_MAJOR
#define AB(I, J) ab[(J-1)*pdab + ku + I - J]
#define B(I, J)  b[(J-1)*pdb + I - 1]
  order = Nag_ColMajor;
#else
#define AB(I, J) ab[(I-1)*pdab + kl + J - I]
#define B(I, J)  b[(I-1)*pdb + J - 1]
  order = Nag_RowMajor;
#endif

  INIT_FAIL(fail);

  printf("nag_zgbsvx (f07bpc) Example Program Results\n\n");

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

  scanf("%ld%ld%ld%ld%*[^\n]", &n,
         &nrhs, &kl, &ku);

  if (n < 0 || kl < 0 || ku < 0 || nrhs < 0)
    {
      printf("Invalid n or kl or ku or nrhs\n");
      exit_status = 1;
      goto END;
    }
  /* Allocate memory */
  if (!(ab = NAG_ALLOC((kl+ku+1) * n, Complex)) ||
      !(afb = NAG_ALLOC((2*kl+ku+1) * n, Complex)) ||
      !(b = NAG_ALLOC(n * nrhs, Complex)) ||
      !(x = NAG_ALLOC(n * nrhs, Complex)) ||
      !(berr = NAG_ALLOC(nrhs, double)) ||
      !(c = NAG_ALLOC(n, double)) ||
      !(ferr = NAG_ALLOC(nrhs, double)) ||
      !(r = NAG_ALLOC(n, double)) ||
      !(ipiv = NAG_ALLOC(n, Integer)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
  pdab = kl+ku+1;
  pdafb = 2*kl+ku+1;
#ifdef NAG_COLUMN_MAJOR
      pdb = n;
      pdx = n;
#else
      pdb = nrhs;
      pdx = nrhs;
#endif

  /* Read the band matrix A and B from data file */
  for (i = 1; i <= n; ++i)
    for (j = MAX(i - kl, 1); j <= MIN(i + ku, n); ++j)
      scanf(" ( %lf , %lf )", &AB(i, j).re, &AB(i, j).im);
  scanf("%*[^\n]");

  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 using  nag_zgbsvx (f07bpc). */
  nag_zgbsvx(order, Nag_EquilibrateAndFactor, Nag_NoTrans, n, kl, ku, nrhs, ab,
             pdab, afb, pdafb, ipiv, &equed, r, c, b, pdb, x, pdx, &rcond,
	     ferr, berr, &growth_factor, &fail);
  if (fail.code != NE_NOERROR && fail.code != NE_SINGULAR)
    {
      printf("Error from nag_zgbsvx (f07bpc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print solution usbing nag_gen_complx_mat_print_comp (x04dbc). */
  fflush(stdout);
  nag_gen_complx_mat_print_comp(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n,
                                nrhs, x, pdx, Nag_BracketForm, "%7.4f",
                                "Solution(s)", Nag_IntegerLabels, 0,
                                Nag_IntegerLabels, 0, 80, 0, 0, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n",
	     fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print error bounds, condition number, the form of equilibration 
   * and the pivot growth factor
   */
  printf("\nBackward errors (machine-dependent)\n");
  for (j = 1; j <= nrhs; ++j) 
    printf("%11.1e%s", berr[j - 1], j%7 == 0?"\n":" ");

  printf("\n\nEstimated forward error bounds (machine-dependent)\n");
  for (j = 1; j <= nrhs; ++j)
    printf("%11.1e%s", ferr[j - 1], j%7 == 0?"\n":" ");

  printf("\nEstimate of reciprocal condition number\n%11.1e\n\n", rcond);
  if (equed == Nag_NoEquilibration)
    printf("A has not been equilibrated\n");
  else if (equed == Nag_RowEquilibration)
    printf("A has been row scaled as diag(R)*A\n");
  else if (equed == Nag_ColumnEquilibration)
    printf("A has been column scaled as A*diag(C)\n");
  else if (equed == Nag_RowAndColumnEquilibration)
    printf("A has been row and column scaled as diag(R)*A*diag(C)\n");

  printf("\nEstimate of reciprocal pivot growth factor\n%11.1e\n",
          growth_factor);
  if (fail.code == NE_SINGULAR)
    printf("Error from nag_zgbsvx (f07bpc).\n%s\n", fail.message);
 END:
  if (ab) NAG_FREE(ab);
  if (afb) NAG_FREE(afb);
  if (b) NAG_FREE(b);
  if (x) NAG_FREE(x);
  if (berr) NAG_FREE(berr);
  if (c) NAG_FREE(c);
  if (ferr) NAG_FREE(ferr);
  if (r) NAG_FREE(r);
  if (ipiv) NAG_FREE(ipiv);

  return exit_status;
}

#undef AB
#undef B