/* nag_zhbevd (f08hqc) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagf08.h>
#include <nagx04.h>

int main(int argc, char *argv[])
{
  FILE          *fpin, *fpout;
  char          *outfile = 0;
  /* Scalars */
  Integer       i, j, k, kd, n, pdab, pdz, w_len;
  Integer       exit_status = 0;
  NagError      fail;
  Nag_JobType   job;
  Nag_UploType  uplo;
  Nag_OrderType order;
  /* Arrays */
  char          nag_enum_arg[40];
  Complex       *ab = 0, *z = 0;
  double        *w = 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);

  /* Check for command-line IO options */
  fpin = nag_example_file_io(argc, argv, "-data", NULL);
  fpout = nag_example_file_io(argc, argv, "-results", NULL);
  (void) nag_example_file_io(argc, argv, "-nag_write", &outfile);
  fprintf(fpout, "nag_zhbevd (f08hqc) Example Program Results\n\n");

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

  /* Allocate memory */
  if (!(ab = NAG_ALLOC(pdab * n, Complex)) ||
      !(w = NAG_ALLOC(w_len, double)) ||
      !(z = NAG_ALLOC(n * n, Complex)))
    {
      fprintf(fpout, "Allocation failure\n");
      exit_status = -1;
      goto END;
    }
  /* Read whether Upper or Lower part of A is stored */
  fscanf(fpin, "%s%*[^\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);
  /* Read A from data file */
  k = kd + 1;
  if (uplo == Nag_Upper)
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = i; j <= MIN(i + kd, n); ++j)
            {
              fscanf(fpin, " ( %lf , %lf )", &AB_UPPER(i, j).re,
                     &AB_UPPER(i, j).im);
            }
        }
      fscanf(fpin, "%*[^\n] ");
    }
  else
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = MAX(1, i - kd); j <= i; ++j)
            {
              fscanf(fpin, " ( %lf , %lf )", &AB_LOWER(i, j).re,
                     &AB_LOWER(i, j).im);
            }
        }
      fscanf(fpin, "%*[^\n] ");
    }
  /* Read type of job to be performed */
  fscanf(fpin, "%s%*[^\n] ", nag_enum_arg);
  job = (Nag_JobType) nag_enum_name_to_value(nag_enum_arg);
  /* Calculate all the eigenvalues and eigenvectors of A */
  /* nag_zhbevd (f08hqc).
   * All eigenvalues and optionally all eigenvectors of
   * complex Hermitian band matrix (divide-and-conquer)
   */
  nag_zhbevd(order, job, uplo, n, kd, ab, pdab, w, z, pdz, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_zhbevd (f08hqc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Print eigenvalues and eigenvectors */
  fprintf(fpout, " Eigenvalues\n");
  for (i = 0; i < n; ++i)
    fprintf(fpout, "   %5ld     %8.4f\n", i + 1, w[i]);
  fprintf(fpout, "\n");
  /* nag_gen_complx_mat_print_comp (x04dbc).
   * Print complex general matrix (comprehensive)
   */
  if (outfile) fclose(fpout);
  nag_gen_complx_mat_print_comp(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n,
                                n, z, pdz, Nag_AboveForm, "%7.4f",
                                "Eigenvectors", Nag_IntegerLabels, 0,
                                Nag_IntegerLabels, 0, 80, 0, outfile, &fail);
  if (outfile && !(fpout = fopen(outfile, "a")))
    {
      exit_status = 2;
      goto END;
    }
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout,
              "Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }
 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  if (ab) NAG_FREE(ab);
  if (w) NAG_FREE(w);
  if (z) NAG_FREE(z);
  return exit_status;
}