/* nag_dgebrd (f08kec) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

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

int main(void)
{
  /* Scalars */
  Integer  i, j, m, n, pda, d_len, e_len, tauq_len, taup_len;
  Integer  exit_status=0;
  NagError fail;
  Nag_OrderType order;
  /* Arrays */
  double *a=0, *d=0, *e=0, *taup=0, *tauq=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);
  Vprintf("f08kec Example Program Results\n");

  /* Skip heading in data file */
  Vscanf("%*[^\n] ");
  Vscanf("%ld%ld%*[^\n] ", &m, &n);
#ifdef NAG_COLUMN_MAJOR
  pda = m;
#else
  pda = n;
#endif
  d_len = MIN(m,n);
  e_len = MIN(m,n)-1;
  tauq_len = MIN(m,n);
  taup_len = MIN(m,n);

  /* Allocate memory */
  if ( !(a = NAG_ALLOC(m * n, double)) ||
       !(d = NAG_ALLOC(d_len, double)) ||
       !(e = NAG_ALLOC(e_len, double)) ||
       !(taup = NAG_ALLOC(taup_len, double)) ||
       !(tauq = NAG_ALLOC(tauq_len, double)) )
    {
      Vprintf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* Read A from data file */
  for (i = 1; i <= m; ++i)
    {
      for (j = 1; j <= n; ++j)
        Vscanf("%lf", &A(i,j));
    }
  Vscanf("%*[^\n] ");

  /* Reduce A to bidiagonal form */
  f08kec(order, m, n, a, pda, d, e, tauq, taup, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from f08kec.\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print bidiagonal form */
  Vprintf("\nDiagonal\n");
  for (i = 1; i <= MIN(m,n); ++i)
    Vprintf("%9.4f%s", d[i-1], i%8==0 ?"\n":" ");
  if (m >= n)
    Vprintf("\nSuper-diagonal\n");
  else
    Vprintf("\nSub-diagonal\n");
  for (i = 1; i <= MIN(m,n) - 1; ++i)
    Vprintf("%9.4f%s", e[i-1], i%8==0 ?"\n":" ");
  Vprintf("\n");

 END:
  if (a) NAG_FREE(a);
  if (d) NAG_FREE(d);
  if (e) NAG_FREE(e);
  if (taup) NAG_FREE(taup);
  if (tauq) NAG_FREE(tauq);

  return exit_status;
}