/* nag_zungtr (f08ftc) 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(void)
{
  /* Scalars */
  Integer  i, j, n, pda, pdz, d_len, e_len, tau_len;
  Integer  exit_status=0;
  NagError fail;
  Nag_UploType  uplo;
  Nag_OrderType order;
  /* Arrays */
  char    uplo_char[2];
  Complex *a=0, *tau=0, *z=0;
  double  *d=0, *e=0;

#ifdef NAG_COLUMN_MAJOR
#define A(I,J) a[(J-1)*pda + I - 1]
#define Z(I,J) z[(J-1)*pdz + I - 1]
  order = Nag_ColMajor;
#else
#define A(I,J) a[(I-1)*pda + J - 1]
#define Z(I,J) z[(I-1)*pdz + J - 1]
  order = Nag_RowMajor;
#endif

  INIT_FAIL(fail);
  Vprintf("nag_zungtr (f08ftc) Example Program Results\n");

  /* Skip heading in data file */
  Vscanf("%*[^\n] ");
  Vscanf("%ld%*[^\n] ", &n);
#ifdef NAG_COLUMN_MAJOR
  pda = n;
  pdz = n;
#else
  pda = n;
  pdz = n;
#endif

  tau_len = n-1;
  d_len = n;
  e_len = n-1;
  /* Allocate memory */
  if ( !(a = NAG_ALLOC(n * n, Complex)) ||
       !(tau = NAG_ALLOC(tau_len, Complex)) ||
       !(z = NAG_ALLOC(n * n, Complex)) ||
       !(d = NAG_ALLOC(d_len, double)) ||
       !(e = NAG_ALLOC(e_len, double)) )
    {
      Vprintf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* Read A from data file */
  Vscanf(" ' %1s '%*[^\n] ", uplo_char);
  if (*(unsigned char *)uplo_char == 'L')
    uplo = Nag_Lower;
  else if (*(unsigned char *)uplo_char == 'U')
    uplo = Nag_Upper;
  else
    {
      Vprintf("Unrecognised character for Nag_UploType type\n");
      exit_status = -1;
      goto END;
    }
  if (uplo == Nag_Upper)
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = i; j <= n; ++j)
            Vscanf(" ( %lf , %lf )", &A(i,j).re, &A(i,j).im);
        }
      Vscanf("%*[^\n] ");
    }
  else
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = 1; j <= i; ++j)
            Vscanf(" ( %lf , %lf )", &A(i,j).re, &A(i,j).im);
        }
      Vscanf("%*[^\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)
    {
      Vprintf("Error from nag_zhetrd (f08fsc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Copy A into Z */
  if (uplo == Nag_Upper)
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = i; j <= n; ++j)
            {
              Z(i,j).re = A(i,j).re;
              Z(i,j).im = A(i,j).im;
            }
        }
    }
  else
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = 1; j <= i; ++j)
            {
              Z(i,j).re = A(i,j).re;
              Z(i,j).im = A(i,j).im;
            }
        }
    }
  /* Form Q explicitly, storing the result in Z */
  /* nag_zungtr (f08ftc).
   * Generate unitary transformation matrix from reduction to
   * tridiagonal form determined by nag_zhetrd (f08fsc)
   */
  nag_zungtr(order, uplo, n, z, pdz, tau, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_zungtr (f08ftc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Calculate all the eigenvalues and eigenvectors of A */
  /* nag_zsteqr (f08jsc).
   * All eigenvalues and eigenvectors of real symmetric
   * tridiagonal matrix, reduced from complex Hermitian
   * matrix, using implicit QL or QR
   */
  nag_zsteqr(order, Nag_UpdateZ, n, d, e, z, pdz, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_zsteqr (f08jsc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Print eigenvalues and eigenvectors */
  Vprintf("\nEigenvalues\n");
  for (i = 1; i <= n; ++i)
    Vprintf("%9.4f%s", d[i-1], i%4==0 ?"\n":" ");
  Vprintf("\n");
  /* nag_gen_complx_mat_print_comp (x04dbc).
   * Print complex general matrix (comprehensive)
   */
  nag_gen_complx_mat_print_comp(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n,
                                z, pdz, Nag_BracketForm, "%7.4f",
                                "Eigenvectors", 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;
    }
 END:
  if (a) NAG_FREE(a);
  if (tau) NAG_FREE(tau);
  if (z) NAG_FREE(z);
  if (d) NAG_FREE(d);
  if (e) NAG_FREE(e);

  return exit_status;
}