/* nag_complex_band_lin_solve (f04cbc) Example Program.
 *
 * Copyright 2004 Numerical Algorithms Group.
 *
 * Mark 8, 2004.
 */

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagf04.h>
#include <nagx04.h>

int main(void)
{

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

  /* Arrays */
  char *clabs=0, *rlabs=0;
  Complex *ab=0, *b=0;
  Integer *ipiv=0;

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


#ifdef NAG_COLUMN_MAJOR
#define AB(I,J) ab[(J-1)*pdab + kl + 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

  exit_status = 0;
  INIT_FAIL(fail);

  Vprintf("nag_complex_band_lin_solve (f04cbc)"
          " Example Program Results\n\n");

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

  Vscanf("%ld%ld%ld%ld%*[^\n] ",
         &n, &kl, &ku,  &nrhs);
  if (n>0 && kl>0 && ku>0 && nrhs>0)
    {
      /* Allocate memory */
      if ( !(clabs = NAG_ALLOC(2, char)) ||
           !(rlabs = NAG_ALLOC(2, char)) ||
           !(ab = NAG_ALLOC((2*kl+ku+1)*n, Complex)) ||
           !(b = NAG_ALLOC(n*nrhs, Complex)) ||
           !(ipiv = NAG_ALLOC(n, Integer)) )
        {
          Vprintf("Allocation failure\n");
          exit_status = -1;
          goto END;
        }
      pdab = 2*kl+ku+1;
#ifdef NAG_COLUMN_MAJOR
      pdb = n;
#else
      pdb = nrhs;
#endif
    }
  else
    {
      Vprintf("%s\n", "One or more of NMAX, KLMAX, KUMAX or NRHSMX is"
              " too small");
      exit_status = 1;
      return exit_status;

    }

  /* Read A and B 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] ");

  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] ");

  /* Solve the equations AX = B for X */
  /* nag_complex_band_lin_solve (f04cbc).
   * Computes the solution and error-bound to a complex banded
   * system of linear equations
   */
  nag_complex_band_lin_solve(order, n, kl, ku, nrhs, ab, pdab, ipiv, b,
                             pdb, &rcond, &errbnd, &fail);
  if (fail.code == NE_NOERROR)
    {

      /* Print solution, estimate of condition number and approximate */
      /* error bound */
      /* nag_gen_complx_mat_print_comp (x04dbc).
       * Print complex general matrix (comprehensive)
       */
      nag_gen_complx_mat_print_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)
        {
          Vprintf("Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n",
                  fail.message);
          exit_status = 1;
          goto END;
        }

      Vprintf("\n%s\n%4s%9.1e\n\n", "Estimate of condition number", "",
              1.0/rcond);
      Vprintf("\n%s\n%4s%9.1e\n\n",
              "Estimate of error bound for computed solutions", "",
              errbnd);
    }
  if (fail.code == NE_RCOND)
    {

      /* Matrix A is numerically singular.  Print estimate of */
      /* reciprocal of condition number and solution */
      Vprintf("\n%s\n%4s%9.1e\n\n\n",
              "Estimate of reciprocal of condition number", "", rcond);
      /* nag_gen_complx_mat_print_comp (x04dbc), see above. */
      nag_gen_complx_mat_print_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)
        {
          Vprintf("Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n",
                  fail.message);
          exit_status = 1;
          goto END;
        }
    }
  if (fail.code == NE_SINGULAR)
    {
      /* The upper triangular matrix U is exactly singular.  Print */
      /* details of factorization */

      Vprintf("\n");
      /* nag_band_complx_mat_print_comp (x04dfc).
       * Print complex packed banded matrix (comprehensive)
       */
      nag_band_complx_mat_print_comp(order, n, n, kl, kl + ku, ab, pdab,
                                     Nag_BracketForm, "%7.4f",
                                     "Details of factorization",
                                     Nag_IntegerLabels, 0,
                                     Nag_IntegerLabels, 0, 80, 0, 0,
                                     &fail);
      if (fail.code != NE_NOERROR)
        {
          Vprintf("Error from nag_band_complx_mat_print_comp (x04dfc).\n%s\n",
                  fail.message);
          exit_status = 1;
          goto END;
        }

      /* Print pivot indices */

      Vprintf("\n%s\n",   "Pivot indices");
      for (i = 1; i <= n; ++i)
        {
          Vprintf("%11ld%s", ipiv[i - 1],
                  i%7 == 0 || i == n ?"\n":" ");
        }
      Vprintf("\n");
    }
 END:
  if (clabs) NAG_FREE(clabs);
  if (rlabs) NAG_FREE(rlabs);
  if (ab) NAG_FREE(ab);
  if (b) NAG_FREE(b);
  if (ipiv) NAG_FREE(ipiv);

  return exit_status;
}