/* nag_real_svd (f02wec) Example Program.
 *
 * Copyright 1990 Numerical Algorithms Group.
 *
 * Mark 1, 1990.
 * Mark 8 revised, 2004.
 */

#include <nag.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <nagf02.h>

#define EX1_MMAX 20
#define EX1_NMAX 10


static int ex1(void), ex2(void);

int main(void)
{

  Integer exit_status_ex1=0;
  Integer exit_status_ex2=0;

  Vprintf("nag_real_svd (f02wec) Example Program Results\n");
  Vscanf(" %*[^\n]");  /* Skip heading in data file */

  exit_status_ex1 = ex1();
  exit_status_ex2 = ex2();

  return exit_status_ex1 == 0 && exit_status_ex2 == 0 ? 0 : 1;
}

#define A(I,J) a[(I)*tda + J]
#define B(I,J) b[(I)*tdb + J]
#define PT(I,J) pt[(I)*tdpt + J]
#define Q(I,J) q[(I)*tdq + J]
static int ex1(void)
{
  Nag_Boolean wantp, wantq;
  Integer exit_status=0, failinfo, i, iter, j, m, n, ncolb, tda, tdb, tdpt;
  NagError fail;
  double *a=0, *b=0, *dummy=0, *e=0, *pt=0, *sv=0;

  INIT_FAIL(fail);


  Vprintf("Example 1\n");
  Vscanf(" %*[^\n]");  /* Skip Example 1 heading */
  Vscanf(" %*[^\n]");

  Vscanf("%ld%ld", &m, &n);
  if (m>=0 && n>=0)
    {
      ncolb = 1;
      if ( !( a = NAG_ALLOC(m*n, double)) ||
           !( b = NAG_ALLOC(m*ncolb, double)) ||
           !( e = NAG_ALLOC(MIN(m,n)-1, double)) ||
           !( pt = NAG_ALLOC(n*n, double)) ||
           !( sv = NAG_ALLOC(MIN(m,n), double)) ||
           !( dummy = NAG_ALLOC(1, double)) )
        {
          Vprintf("Allocation failure\n");
          exit_status = -1;
          goto END;
        }
      tda = n;
      tdb = ncolb;
      tdpt = n;
    }
  else
    {
      Vprintf("Invalid m or n.\n");
      exit_status = 1;
      return exit_status;
    }
  Vscanf(" %*[^\n]");
  for (i = 0; i < m; ++i)
    for (j = 0; j < n; ++j)
      Vscanf("%lf", &A(i,j));
  Vscanf(" %*[^\n]");
  for (i = 0; i < m; ++i)
    for (j = 0; j < ncolb; ++j)
      Vscanf("%lf", &B(i,j));

  /* Find the SVD of A. */
  wantq = Nag_TRUE;
  wantp = Nag_TRUE;
  /* nag_real_svd (f02wec).
   * SVD of real matrix
   */
  nag_real_svd(m, n, a, tda, ncolb, b, tdb, wantq,
               dummy, (Integer)1, sv, wantp, pt, tdpt, &iter,
               e, &failinfo, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_real_svd (f02wec).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  Vprintf("Singular value decomposition of A\n\n");
  Vprintf("Singular values\n");
  for (i = 0; i < n; ++i)
    Vprintf(" %8.4f", sv[i]);
  Vprintf("\n\n");
  Vprintf("Left-hand singular vectors, by column\n");
  for (i = 0; i < m; ++i)
    {
      for (j = 0; j < n; ++j)
        Vprintf(" %8.4f", A(i,j));
      Vprintf("\n");
    }
  Vprintf("\n");
  Vprintf("Right-hand singular vectors, by column\n");
  for (i = 0; i < n; ++i)
    {
      for (j = 0; j < n; ++j)
        Vprintf(" %8.4f", PT(j,i));
      Vprintf("\n");
    }
  Vprintf("\n");
  Vprintf("Vector Q'*B\n");
  for (i = 0; i < m; ++i)
    Vprintf(" %8.4f", b[i]);
  Vprintf("\n\n");
 END:
  if (a) NAG_FREE(a);
  if (b) NAG_FREE(b);
  if (e) NAG_FREE(e);
  if (pt) NAG_FREE(pt);
  if (sv) NAG_FREE(sv);
  if (dummy) NAG_FREE(dummy);
  return exit_status;
}

static int ex2(void)
{

  Nag_Boolean wantp, wantq;
  Integer exit_status=0, failinfo, i, iter, j, m, n, ncolb, tda, tdq;
  NagError fail;
  double *a=0, *dummy=0, *e=0, *q=0, *sv=0;

  INIT_FAIL(fail);

  Vprintf("\nExample 2\n");
  Vscanf(" %*[^\n]");  /* Skip Example 2 heading */
  Vscanf(" %*[^\n]");

  Vscanf("%ld%ld", &m, &n);
  if (m>=0 && n>=0)
    {
      if ( !( a = NAG_ALLOC(m*n, double)) ||
           !( q = NAG_ALLOC(m*m, double)) ||
           !( e = NAG_ALLOC(MIN(m,n)-1, double)) ||
           !( sv = NAG_ALLOC(MIN(m,n), double)) ||
           !( dummy = NAG_ALLOC(1, double)) )
        {
          Vprintf("Allocation failure\n");
          exit_status = -1;
          goto END;
        }
      tda = n;
      tdq = m;

    }
  else
    {
    }
  Vscanf(" %*[^\n]");
  for (i = 0; i < m; ++i)
    for (j = 0; j < n; ++j)
      Vscanf("%lf", &A(i,j));

  /* Find the SVD of A. */
  wantq = Nag_TRUE;
  wantp = Nag_TRUE;
  ncolb = 0;
  /* nag_real_svd (f02wec), see above. */
  nag_real_svd(m, n, a, tda, ncolb, dummy, (Integer)1, wantq,
               q, tdq, sv, wantp, dummy, (Integer)1, &iter,
               e, &failinfo, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_real_svd (f02wec).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  Vprintf("Singular value decomposition of A\n\n\n");
  Vprintf("Singular values\n\n");
  for (i = 0; i < m; ++i)
    Vprintf(" %8.4f", sv[i]);
  Vprintf("\n\n");
  Vprintf("Left-hand singular vectors, by column\n\n");
  for (i = 0; i < m; ++i)
    {
      for (j = 0; j < m; ++j)
        Vprintf(" %8.4f", Q(i,j));
      Vprintf("\n");
    }
  Vprintf("Right-hand singular vectors, by column\n\n");
  for (i = 0; i < n; ++i)
    {
      for (j = 0; j < m; ++j)
        Vprintf(" %8.4f", A(j,i));
      Vprintf("\n");
    }
 END:
  if (a) NAG_FREE(a);
  if (q) NAG_FREE(q);
  if (e) NAG_FREE(e);
  if (sv) NAG_FREE(sv);
  if (dummy) NAG_FREE(dummy);
  return exit_status;
}