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

#include <nag.h>
#include <nagx04.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <nagf02.h>

#define EX1_MMAX 20
#define EX1_NMAX 10


static int ex1(FILE *fpin, FILE *fpout), ex2(FILE *fpin, FILE *fpout);

int main(int argc, char *argv[])
{
  FILE     *fpin, *fpout;
  Integer  exit_status_ex1 = 0;
  Integer  exit_status_ex2 = 0;
  NagError fail;

  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);
  fprintf(fpout, "nag_real_svd (f02wec) Example Program Results\n");
  fscanf(fpin, " %*[^\n]");  /* Skip heading in data file */

  exit_status_ex1 = ex1(fpin, fpout);
  exit_status_ex2 = ex2(fpin, fpout);

  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  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(FILE *fpin, FILE *fpout)
{
  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);

  fprintf(fpout, "Example 1\n");
  fscanf(fpin, " %*[^\n]");  /* Skip Example 1 heading */
  fscanf(fpin, " %*[^\n]");

  fscanf(fpin, "%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)))
        {
          fprintf(fpout, "Allocation failure\n");
          exit_status = -1;
          goto END;
        }
      tda = n;
      tdb = ncolb;
      tdpt = n;
    }
  else
    {
      fprintf(fpout, "Invalid m or n.\n");
      exit_status = 1;
      return exit_status;
    }
  fscanf(fpin, " %*[^\n]");
  for (i = 0; i < m; ++i)
    for (j = 0; j < n; ++j)
      fscanf(fpin, "%lf", &A(i, j));
  fscanf(fpin, " %*[^\n]");
  for (i = 0; i < m; ++i)
    for (j = 0; j < ncolb; ++j)
      fscanf(fpin, "%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)
    {
      fprintf(fpout, "Error from nag_real_svd (f02wec).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  fprintf(fpout, "Singular value decomposition of A\n\n");
  fprintf(fpout, "Singular values\n");
  for (i = 0; i < n; ++i)
    fprintf(fpout, " %8.4f", sv[i]);
  fprintf(fpout, "\n\n");
  fprintf(fpout, "Left-hand singular vectors, by column\n");
  for (i = 0; i < m; ++i)
    {
      for (j = 0; j < n; ++j)
        fprintf(fpout, " %8.4f", A(i, j));
      fprintf(fpout, "\n");
    }
  fprintf(fpout, "\n");
  fprintf(fpout, "Right-hand singular vectors, by column\n");
  for (i = 0; i < n; ++i)
    {
      for (j = 0; j < n; ++j)
        fprintf(fpout, " %8.4f", PT(j, i));
      fprintf(fpout, "\n");
    }
  fprintf(fpout, "\n");
  fprintf(fpout, "Vector Q'*B\n");
  for (i = 0; i < m; ++i)
    fprintf(fpout, " %8.4f", b[i]);
  fprintf(fpout, "\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(FILE *fpin, FILE *fpout)
{
  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);

  fprintf(fpout, "\nExample 2\n");
  fscanf(fpin, " %*[^\n]");  /* Skip Example 2 heading */
  fscanf(fpin, " %*[^\n]");

  fscanf(fpin, "%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)))
        {
          fprintf(fpout, "Allocation failure\n");
          exit_status = -1;
          goto END;
        }
      tda = n;
      tdq = m;
    }
  else
    {
    }
  fscanf(fpin, " %*[^\n]");
  for (i = 0; i < m; ++i)
    for (j = 0; j < n; ++j)
      fscanf(fpin, "%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)
    {
      fprintf(fpout, "Error from nag_real_svd (f02wec).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  fprintf(fpout, "Singular value decomposition of A\n\n\n");
  fprintf(fpout, "Singular values\n\n");
  for (i = 0; i < m; ++i)
    fprintf(fpout, " %8.4f", sv[i]);
  fprintf(fpout, "\n\n");
  fprintf(fpout, "Left-hand singular vectors, by column\n\n");
  for (i = 0; i < m; ++i)
    {
      for (j = 0; j < m; ++j)
        fprintf(fpout, " %8.4f", Q(i, j));
      fprintf(fpout, "\n");
    }
  fprintf(fpout, "Right-hand singular vectors, by column\n\n");
  for (i = 0; i < n; ++i)
    {
      for (j = 0; j < m; ++j)
        fprintf(fpout, " %8.4f", A(j, i));
      fprintf(fpout, "\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;
}