/* nag_zunmhr (f08nuc) 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>
#include <naga02.h>
int main(void)
{
  /* Scalars */
  Integer       i, j, m, n, pda, pdh, pdvl, pdvr, pdz;
  Integer       tau_len, ifaill_len, select_len, w_len;
  Integer       exit_status = 0;
  double        thresh;
  NagError      fail;
  Nag_OrderType order;
  /* Arrays */
  Complex       *a = 0, *h = 0, *vl = 0, *vr = 0, *z = 0, *w = 0, *tau = 0;
  Integer       *ifaill = 0, *ifailr = 0;
  Nag_Boolean   *select = 0;

#ifdef NAG_COLUMN_MAJOR
#define A(I, J) a[(J - 1) * pda + I - 1]
#define H(I, J) h[(J - 1) * pdh + I - 1]
#define VR(I, J) vr[(J - 1) * pdvr + I - 1]
  order = Nag_ColMajor;
#else
#define A(I, J) a[(I - 1) * pda + J - 1]
#define H(I, J) h[(I - 1) * pdh + J - 1]
#define VR(I, J) vr[(I - 1) * pdvr + J - 1]
  order = Nag_RowMajor;
#endif

  INIT_FAIL(fail);

  printf("nag_zunmhr (f08nuc) Example Program Results\n\n");

  /* Skip heading in data file */
  scanf("%*[^\n] ");
  scanf("%ld%*[^\n] ", &n);

  pda = n;
  pdh = n;
  pdvl = n;
  pdvr = n;
  pdz = 1;
  tau_len = n;
  w_len = n;
  ifaill_len = n;
  select_len = n;

  /* Allocate memory */
  if (!(a = NAG_ALLOC(n * n, Complex)) ||
      !(h = NAG_ALLOC(n * n, Complex)) ||
      !(vl = NAG_ALLOC(n * n, Complex)) ||
      !(vr = NAG_ALLOC(n * n, Complex)) ||
      !(z = NAG_ALLOC(1 * 1, Complex)) ||
      !(w = NAG_ALLOC(w_len, Complex)) ||
      !(ifaill = NAG_ALLOC(ifaill_len, Integer)) ||
      !(ifailr = NAG_ALLOC(ifaill_len, Integer)) ||
      !(select = NAG_ALLOC(select_len, Nag_Boolean)) ||
      !(tau = NAG_ALLOC(tau_len, Complex)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
  /* Read A from data file */
  for (i = 1; i <= n; ++i)
    {
      for (j = 1; j <= n; ++j)
        scanf(" ( %lf , %lf )", &A(i, j).re, &A(i, j).im);
    }
  scanf("%*[^\n] ");
  scanf("%lf%*[^\n] ", &thresh);

  /* Reduce A to upper Hessenberg form */
  /* nag_zgehrd (f08nsc).
   * Unitary reduction of complex general matrix to upper
   * Hessenberg form
   */
  nag_zgehrd(order, n, 1, n, a, pda, tau, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_zgehrd (f08nsc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Copy A to H */
  for (i = 1; i <= n; ++i)
    {
      for (j = 1; j <= n; ++j)
        {
          H(i, j).re = A(i, j).re;
          H(i, j).im = A(i, j).im;
        }
    }

  /* Calculate the eigenvalues of H (same as A) */
  /* nag_zhseqr (f08psc).
   * Eigenvalues and Schur factorization of complex upper
   * Hessenberg matrix reduced from complex general matrix
   */
  nag_zhseqr(order, Nag_EigVals, Nag_NotZ, n, 1, n, h, pdh, w,
             z, pdz, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_zhseqr (f08psc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print eigenvalues */
  printf(" Eigenvalues\n");
  for (i = 0; i < n; ++i)
    printf(" (%7.4f,%7.4f)", w[i].re, w[i].im);
  printf("\n");
  for (i = 0; i < n; ++i)
    select[i] = w[i].re < thresh?Nag_TRUE:Nag_FALSE;
  /* Calculate the eigenvectors of H (as specified by SELECT), */
  /* storing the result in VR */
  /* nag_zhsein (f08pxc).
   * Selected right and/or left eigenvectors of complex upper
   * Hessenberg matrix by inverse iteration
   */
  nag_zhsein(order, Nag_RightSide, Nag_HSEQRSource, Nag_NoVec, select,
             n, a, pda, w, vl, pdvl, vr, pdvr, n, &m, ifaill,
             ifailr, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_zhsein (f08pxc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Calculate the eigenvectors of A = Q * VR */
  /* nag_zunmhr (f08nuc).
   * Apply unitary transformation matrix from reduction to
   * Hessenberg form determined by nag_zgehrd (f08nsc)
   */
  nag_zunmhr(order, Nag_LeftSide, Nag_NoTrans, n, m, 1, n, a, pda,
             tau, vr, pdvr, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_zunmhr (f08nuc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Normalize the eigenvectors */
  for(j=1; j<=m; j++)
    {
      for(i=n; i>=1; i--)
        {
          VR(i, j) = nag_complex_divide(VR(i, j), VR(1,j));
        }
    }
  
  /* Print Eigenvectors */
  printf("\n");
  /* nag_gen_complx_mat_print_comp (x04dbc).
   * Print complex general matrix (comprehensive)
   */
  fflush(stdout);
  nag_gen_complx_mat_print_comp(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n,
                                m, vr, pdvr, Nag_BracketForm, "%7.4f",
                                "Contents of array VR", Nag_IntegerLabels, 0,
                                Nag_IntegerLabels, 0, 80, 0, 0, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf(
              "Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }
 END:
  if (a) NAG_FREE(a);
  if (h) NAG_FREE(h);
  if (vl) NAG_FREE(vl);
  if (vr) NAG_FREE(vr);
  if (z) NAG_FREE(z);
  if (w) NAG_FREE(w);
  if (ifaill) NAG_FREE(ifaill);
  if (ifailr) NAG_FREE(ifailr);
  if (select) NAG_FREE(select);
  if (tau) NAG_FREE(tau);
  return exit_status;
}