/* nag_zgbrfs (f07bvc) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

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

int main(void)
{
  /* Scalars */
  Integer  i, ipiv_len, j, kl, ku, n, nrhs, pdab, pdafb, pdb, pdx;
  Integer  exit_status=0;
  NagError fail;
  Nag_OrderType order;

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

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

  INIT_FAIL(fail);
  Vprintf("f07bvc Example Program Results\n\n");

  /* Skip heading in data file */
  Vscanf("%*[^\n] ");
  Vscanf("%ld%ld%ld%ld%*[^\n] ", &n, &nrhs, &kl, &ku);
  ipiv_len = n;
  pdab  = kl + ku + 1;
  pdafb = 2*kl + ku + 1;
#ifdef NAG_COLUMN_MAJOR
  pdb = n;
  pdx = n;
#else
  pdb = nrhs;
  pdx = nrhs;
#endif

  /* Allocate memory */
  if ( !(ab = NAG_ALLOC((kl+ku+1) * n, Complex)) ||
       !(afb = NAG_ALLOC((2*kl+ku+1) * n, Complex)) ||
       !(b = NAG_ALLOC(nrhs * n, Complex)) ||
       !(x = NAG_ALLOC(nrhs * n, Complex)) ||
       !(berr = NAG_ALLOC(nrhs, double)) ||
       !(ferr = NAG_ALLOC(nrhs, double)) ||
       !(ipiv = NAG_ALLOC(ipiv_len, Integer)) )
    {
      Vprintf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
  /* Set A to zero to avoid referencing unitialized elements */
  for (i = 0; i < n*(kl+ku+1); ++i)
    {
      ab[i].re = 0.0;
      ab[i].im = 0.0;
    }
  /* Read A from data file */
  for (i = 1; i <= n; ++i)
    {
      for (j = MAX(i-kl,1); j <= MIN(i+ku,n); ++j)
        Vscanf(" ( %lf , %lf )", &AB(i,j).re, &AB(i,j).im);
    }
  Vscanf("%*[^\n] ");
  /* Read B from data file */
  for (i = 1; i <= n; ++i)
    {
      for (j = 1; j <= nrhs; ++j)
        Vscanf(" ( %lf , %lf )", &B(i,j).re, &B(i,j).im);
    }
  Vscanf("%*[^\n] ");
  /* Copy A to AFB and B to X */
  for (i = 1; i <= n; ++i)
    {
      for (j = MAX(i-kl,1); j <= MIN(i+ku,n); ++j)
        {
          AFB(i,j).re = AB(i,j).re;
          AFB(i,j).im = AB(i,j).im;
        }
    }
  for (i = 1; i <= n; ++i)
    {
      for (j = 1; j <= nrhs; ++j)
        {
          X(i,j).re = B(i,j).re;
          X(i,j).im = B(i,j).im;
        }
    }
  /* Factorize A in the array AFB */
  f07brc(order, n, n, kl, ku, afb, pdafb, ipiv, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from f07brc.\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Compute solution in the array X */
  f07bsc(order, Nag_NoTrans, n, kl, ku, nrhs, afb, pdafb, ipiv,
         x, pdx, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from f07bsc.\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Improve solution, and compute backward errors and  */
  /* estimated bounds on the forward errors */
  f07bvc(order, Nag_NoTrans, n, kl, ku, nrhs, ab, pdab, afb, pdafb,
         ipiv, b, pdb, x, pdx, ferr, berr, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from f07bvc.\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Print solution */
  x04dbc(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)
    {
      Vprintf("Error from x04dbc.\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Print forward and backward errors */
  Vprintf("\nBackward errors (machine-dependent)\n");

  for (j = 1; j <= nrhs; ++j)
    Vprintf("%11.1e%s", berr[j-1], j%7==0 ?"\n":" ");

  Vprintf("\nEstimated forward error bounds (machine-dependent)\n");

  for (j = 1; j <= nrhs; ++j)
    Vprintf("%11.1e%s", ferr[j-1], j%7==0 ?"\n":" ");
  Vprintf("\n");
 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 (ferr) NAG_FREE(ferr);
  if (ipiv) NAG_FREE(ipiv);
  return exit_status;
}