/* nag_zpbcon (f07huc) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <naga02.h>
#include <nagf07.h>
#include <nagf16.h>
#include <nagx02.h>

int main(void)
{
  /* Scalars */
  Integer  i, j, k, kd, n, pdab;
  Integer  exit_status=0;
  double   anorm, rcond;
  NagError fail;
  Nag_UploType  uplo_enum;
  Nag_OrderType order;

  /* Arrays */
  char     uplo[2];
  Complex  *ab=0;

#ifdef NAG_COLUMN_MAJOR
#define AB_UPPER(I,J) ab[(J-1)*pdab + k + I - J - 1]
#define AB_LOWER(I,J) ab[(J-1)*pdab + I - J]
  order = Nag_ColMajor;
#else
#define AB_UPPER(I,J) ab[(I-1)*pdab + J - I]
#define AB_LOWER(I,J) ab[(I-1)*pdab + k + J - I - 1]
  order = Nag_RowMajor;
#endif

  INIT_FAIL(fail);
  Vprintf("nag_zpbcon (f07huc) Example Program Results\n\n");

  /* Skip heading in data file */
  Vscanf("%*[^\n] ");
  Vscanf("%ld%ld%*[^\n] ", &n, &kd);
  pdab = kd + 1;

  /* Allocate memory */
  if ( !(ab = NAG_ALLOC((kd+1) * n, Complex)) )
    {
      Vprintf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* Read A from data file */
  Vscanf(" ' %1s '%*[^\n] ", uplo);
  if (*(unsigned char *)uplo == 'L')
    uplo_enum = Nag_Lower;
  else if (*(unsigned char *)uplo == 'U')
    uplo_enum = Nag_Upper;
  else
    {
      Vprintf("Unrecognised character for Nag_UploType type\n");
      exit_status = -1;
      goto END;
    }
  k = kd + 1;
  if (uplo_enum == Nag_Upper)
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = i; j <= MIN(i+kd,n); ++j)
            {
              Vscanf(" ( %lf , %lf )", &AB_UPPER(i,j).re,
                     &AB_UPPER(i,j).im);
            }
        }
      Vscanf("%*[^\n] ");
    }
  else
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = MAX(1,i-kd); j <= i; ++j)
            {
              Vscanf(" ( %lf , %lf )", &AB_LOWER(i,j).re,
                     &AB_LOWER(i,j).im);
            }
        }
      Vscanf("%*[^\n] ");
    }
  /* Compute norm of A */
  /* nag_zhb_norm (f16uec).
   * 1-norm, infinity-norm, Frobenius norm, largest absolute
   * element, complex Hermitian band matrix
   */
  nag_zhb_norm(order, Nag_OneNorm, uplo_enum, n, kd, ab, pdab, &anorm, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_zhb_norm (f16uec).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Factorize A */
  /* nag_zpbtrf (f07hrc).
   * Cholesky factorization of complex Hermitian
   * positive-definite band matrix
   */
  nag_zpbtrf(order, uplo_enum, n, kd, ab, pdab, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_zpbtrf (f07hrc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Estimate condition number */
  /* nag_zpbcon (f07huc).
   * Estimate condition number of complex Hermitian
   * positive-definite band matrix, matrix already factorized
   * by nag_zpbtrf (f07hrc)
   */
  nag_zpbcon(order, uplo_enum, n, kd, ab, pdab, anorm, &rcond, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_zpbcon (f07huc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* nag_machine_precision (x02ajc).
   * The machine precision
   */
  if (rcond >= X02AJC)
    Vprintf("Estimate of condition number =%10.2e\n\n", 1.0/rcond);
  else
    Vprintf("A is singular to working precision\n");
 END:
  if (ab) NAG_FREE(ab);
  return exit_status;
}