/* nag_zunmtr (f08fuc) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 * Mark 7b revised, 2004.
 */

#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, m, n, nsplit, pda, pdz, d_len, e_len;
  Integer       exit_status = 0;
  double        vl = 0.0, vu = 0.0;
  NagError      fail;
  Nag_UploType  uplo;
  Nag_OrderType order;
  /* Arrays */
  char          nag_enum_arg[40];
  Integer       *iblock = 0, *ifailv = 0, *isplit = 0;
  Complex       *a = 0, *tau = 0, *z = 0;
  double        *d = 0, *e = 0, *w = 0;

#ifdef NAG_COLUMN_MAJOR
#define A(I, J) a[(J - 1) * pda + I - 1]
  order = Nag_ColMajor;
#else
#define A(I, J) a[(I - 1) * pda + J - 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_zunmtr (f08fuc) Example Program Results\n\n");

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

  d_len = n;
  e_len = n - 1;
  /* Allocate memory */
  if (!(a = NAG_ALLOC(n * n, Complex)) ||
      !(d = NAG_ALLOC(d_len, double)) ||
      !(e = NAG_ALLOC(e_len, double)) ||
      !(iblock = NAG_ALLOC(n, Integer)) ||
      !(ifailv = NAG_ALLOC(n, Integer)) ||
      !(isplit = NAG_ALLOC(n, Integer)) ||
      !(w = NAG_ALLOC(n, double)) ||
      !(tau = NAG_ALLOC(n-1, Complex)) ||
      !(z = NAG_ALLOC(n * n, Complex)))
    {
      fprintf(fpout, "Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* Read A from data file */
  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);
  if (uplo == Nag_Upper)
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = i; j <= n; ++j)
            fscanf(fpin, " ( %lf , %lf )", &A(i, j).re, &A(i, j).im);
        }
      fscanf(fpin, "%*[^\n] ");
    }
  else
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = 1; j <= i; ++j)
            fscanf(fpin, " ( %lf , %lf )", &A(i, j).re, &A(i, j).im);
        }
      fscanf(fpin, "%*[^\n] ");
    }

  /* Reduce A to tridiagonal form T = (Q**H)*A*Q */
  /* nag_zhetrd (f08fsc).
   * Unitary reduction of complex Hermitian matrix to real
   * symmetric tridiagonal form
   */
  nag_zhetrd(order, uplo, n, a, pda, d, e, tau, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_zhetrd (f08fsc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Calculate the two smallest eigenvalues of T (same as A) */
  /* nag_dstebz (f08jjc).
   * Selected eigenvalues of real symmetric tridiagonal matrix
   * by bisection
   */
  nag_dstebz(Nag_Indices, Nag_ByBlock, n, vl, vu, 1, 2, 0.0,
             d, e, &m, &nsplit, w, iblock, isplit, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_dstebz (f08jjc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print eigenvalues */
  fprintf(fpout, "Eigenvalues\n");
  for (i = 0; i < m; ++i)
    fprintf(fpout, "%8.4f%s", w[i], (i+1)%8 == 0?"\n":"            ");
  fprintf(fpout, "\n\n");
  /* Calculate the eigenvectors of T storing the result in Z */
  /* nag_zstein (f08jxc).
   * Selected eigenvectors of real symmetric tridiagonal
   * matrix by inverse iteration, storing eigenvectors in
   * complex array
   */
  nag_zstein(order, n, d, e, m, w, iblock, isplit, z, pdz, ifailv,
             &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_zstein (f08jxc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Calculate all the eigenvectors of A = Q*(eigenvectors of T) */
  /* nag_zunmtr (f08fuc).
   * Apply unitary transformation matrix determined by
   * nag_zhetrd (f08fsc)
   */
  nag_zunmtr(order, Nag_LeftSide, uplo, Nag_NoTrans, n, m, a, pda,
             tau, z, pdz, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_zunmtr (f08fuc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Print eigenvectors */
  /* 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,
                                m, z, pdz, Nag_BracketForm, "%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 (a) NAG_FREE(a);
  if (d) NAG_FREE(d);
  if (e) NAG_FREE(e);
  if (iblock) NAG_FREE(iblock);
  if (ifailv) NAG_FREE(ifailv);
  if (isplit) NAG_FREE(isplit);
  if (tau) NAG_FREE(tau);
  if (w) NAG_FREE(w);
  if (z) NAG_FREE(z);

  return exit_status;
}