/* nag_dorgbr (f08kfc) 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(int argc, char *argv[])
{
  FILE          *fpin, *fpout;
  char          *outfile = 0;
  /* Scalars */
  Integer       i, ic, j, m, n, pda, pdc, pdu, pdvt, d_len;
  Integer       e_len, tauq_len, taup_len;
  Integer       exit_status = 0;
  NagError      fail;
  Nag_OrderType order;
  /* Arrays */
  double        *a = 0, *c = 0, *d = 0, *e = 0, *taup = 0, *tauq = 0, *u = 0;
  double        *vt = 0;

#ifdef NAG_COLUMN_MAJOR
#define A(I, J)  a[(J-1)*pda + I - 1]
#define VT(I, J) vt[(J-1)*pdvt + I - 1]
#define U(I, J)  u[(J-1)*pdu + I - 1]
  order = Nag_ColMajor;
#else
#define A(I, J)  a[(I-1)*pda + J - 1]
#define VT(I, J) vt[(I-1)*pdvt + J - 1]
#define U(I, J)  u[(I-1)*pdu + J - 1]
  order = Nag_RowMajor;
#endif

  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);
  (void) nag_example_file_io(argc, argv, "-nag_write", &outfile);
  fprintf(fpout, "nag_dorgbr (f08kfc) Example Program Results\n\n");

  /* Skip heading in data file */
  fscanf(fpin, "%*[^\n] ");

  for (ic = 1; ic <= 2; ++ic)
    {
      fscanf(fpin, "%ld%ld%*[^\n] ", &m, &n);

#ifdef NAG_COLUMN_MAJOR
      pda = m;
      pdu = m;
      pdvt = m;
#else
      pda = n;
      pdu = n;
      pdvt = n;
#endif
      pdc = n;
      d_len = n;
      e_len = n-1;
      tauq_len = n;
      taup_len = n;

      /* Allocate memory */
      if (!(a = NAG_ALLOC(m * n, double)) ||
          !(c = NAG_ALLOC(n * 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)) ||
          !(u = NAG_ALLOC(m * n, double)) ||
          !(vt = NAG_ALLOC(m * n, double)))
        {
          fprintf(fpout, "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)
            fscanf(fpin, "%lf", &A(i, j));
        }
      fscanf(fpin, "%*[^\n] ");

      /* Reduce A to bidiagonal form using  nag_dgebrd (f08kec). */
      nag_dgebrd(order, m, n, a, pda, d, e, tauq, taup, &fail);
      if (fail.code != NE_NOERROR)
        {
          fprintf(fpout, "Error from nag_dgebrd (f08kec).\n%s\n", fail.message);
          exit_status = 1;
          goto END;
        }
      if (m >= n)
        {
          /* Example 1 */
          /* Copy A to VT and U */
          for (i = 1; i <= n; ++i)
            {
              for (j = i; j <= n; ++j)
                VT(i, j) = A(i, j);
            }
          for (i = 1; i <= m; ++i)
            {
              for (j = 1; j <= MIN(i, n); ++j)
                U(i, j) = A(i, j);
            }
          /* nag_dorgbr (f08kfc):                                 */
          /*       Form P**T explicitly, storing the result in VT */
          nag_dorgbr(order, Nag_FormP, n, n, m, vt, pdvt, taup, &fail);
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout, "Error from nag_dorgbr (f08kfc).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }

          /* nag_dorgbr (f08kfc):                             */
          /*       Form Q explicitly, storing the result in U */
          nag_dorgbr(order, Nag_FormQ, m, n, n, u, pdu, tauq, &fail);
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout, "Error from nag_dorgbr (f08kfc).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }

          /* nag_dbdsqr (f08mec): Compute the SVD of A.        */
          nag_dbdsqr(order, Nag_Upper, n, n, m, 0, d, e, vt, pdvt, u,
                     pdu, c, pdc, &fail);
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout, "Error from nag_dbdsqr (f08mec).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }

          /* Print singular values, left & right singular vectors */
          fprintf(fpout, "\n Example 1: singular values\n");
          for (i = 1; i <= n; ++i)
            fprintf(fpout, "%8.4f%s", d[i-1], i%8 == 0?"\n":" ");
          fprintf(fpout, "\n\n");

          /* nag_gen_real_mat_print (x04cac): Print VT. */
          if (outfile) fclose(fpout);
          nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag,
                                 n, n, vt, pdvt,
                                 "Example 1: right singular vectors, by row",
                                 outfile, &fail);
          if (outfile && !(fpout = fopen(outfile, "a")))
            {
              exit_status = 2;
              goto END;
            }
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout,
                      "Error from nag_gen_real_mat_print (x04cac).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }
          fprintf(fpout, "\n");

          /* nag_gen_real_mat_print (x04cac): Print U. */
          if (outfile) fclose(fpout);
          nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag,
                                 m, n, u, pdu,
                                 "Example 1: left singular vectors, by column",
                                 outfile, &fail);
          if (outfile && !(fpout = fopen(outfile, "a")))
            {
              exit_status = 2;
              goto END;
            }
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout,
                      "Error from nag_gen_real_mat_print (x04cac).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }
        }
      else
        {
          /* Example 2 */
          /* Copy A to VT and U */
          for (i = 1; i <= m; ++i)
            {
              for (j = i; j <= n; ++j)
                VT(i, j) = A(i, j);
            }
          for (i = 1; i <= m; ++i)
            {
              for (j = 1; j <= i; ++j)
                U(i, j) = A(i, j);
            }
          /* nag_dorgbr (f08kfc):                                  */
          /*        Form P**T explicitly, storing the result in VT */
          nag_dorgbr(order, Nag_FormP, m, n, m, vt, pdvt, taup, &fail);
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout, "Error from nag_dorgbr (f08kfc).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }
          /* nag_dorgbr (f08kfc):                              */
          /*        Form Q explicitly, storing the result in U */
          nag_dorgbr(order, Nag_FormQ, m, m, n, u, pdu, tauq, &fail);
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout, "Error from nag_dorgbr (f08kfc).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }
          /* nag_dbdsqr (f08mec): Compute the SVD of A */
          nag_dbdsqr(order, Nag_Lower, m, n, m, 0, d, e, vt, pdvt, u,
                     pdu, c, pdc, &fail);
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout, "Error from nag_dbdsqr (f08mec).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }

          /* Print singular values, left & right singular vectors */
          fprintf(fpout, "\n Example 2: singular values\n");
          for (i = 1; i <= m; ++i)
            fprintf(fpout, "%8.4f%s", d[i-1], i%8 == 0?"\n":" ");
          fprintf(fpout, "\n\n");
          /* nag_gen_real_mat_print (x04cac): Print VT */
          if (outfile) fclose(fpout);
          nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag,
                                 m, n, vt, pdvt,
                                 "Example 2: right singular vectors, by row",
                                 outfile, &fail);
          if (outfile && !(fpout = fopen(outfile, "a")))
            {
              exit_status = 2;
              goto END;
            }
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout,
                      "Error from nag_gen_real_mat_print (x04cac).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }
          fprintf(fpout, "\n");
          if (outfile) fclose(fpout);
          /* nag_gen_real_mat_print (x04cac): print U */
          nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag,
                                 m, m, u, pdu,
                                 "Example 2: left singular vectors, by column",
                                 outfile, &fail);
          if (outfile && !(fpout = fopen(outfile, "a")))
            {
              exit_status = 2;
              goto END;
            }
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout,
                      "Error from nag_gen_real_mat_print (x04cac).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }
        }
 END:
      if (a) NAG_FREE(a);
      if (c) NAG_FREE(c);
      if (d) NAG_FREE(d);
      if (e) NAG_FREE(e);
      if (taup) NAG_FREE(taup);
      if (tauq) NAG_FREE(tauq);
      if (u) NAG_FREE(u);
      if (vt) NAG_FREE(vt);
    }
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  return exit_status;
}
#undef A
#undef U
#undef VT