/* nag_dormbr (f08kgc) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagf08.h>
#include <nagf16.h>
#include <nagx04.h>

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

#ifdef NAG_COLUMN_MAJOR
#define A(I, J)  a[(J - 1) * pda + I - 1]
#define U(I, J)  u[(J - 1) * pdu + I - 1]
#define PT(I, J) pt[(J - 1) * pdpt + I - 1]
  order = Nag_ColMajor;
#else
#define A(I, J)  a[(I - 1) * pda + J - 1]
#define U(I, J)  u[(I - 1) * pdu + J - 1]
#define PT(I, J) pt[(I - 1) * pdpt + 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_dormbr (f08kgc) Example Program Results\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;
#else
      pda = n;
#endif
      pdu = m;
      pdpt = n;
      taup_len = n;
      tauq_len = n;
      tau_len = n;
      d_len = n;
      e_len = n - 1;

      /* Allocate memory */
      if (!(a = NAG_ALLOC(m * n, double)) ||
          !(d = NAG_ALLOC(d_len, double)) ||
          !(e = NAG_ALLOC(e_len, double)) ||
          !(pt = NAG_ALLOC(n * n, double)) ||
          !(tau = NAG_ALLOC(tau_len, double)) ||
          !(taup = NAG_ALLOC(taup_len, double)) ||
          !(tauq = NAG_ALLOC(tauq_len, double)) ||
          !(u = NAG_ALLOC(m * m, 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] ");
      if (m >= n)
        {
          /* Example 1. */

          /* nag_dgeqrf (f08aec): Compute the QR factorization of A */
          nag_dgeqrf(order, m, n, a, pda, tau, &fail);
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout, "Error from nag_dgeqrf (f08aec).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }
          /* Copy A to U */
          for (i = 1; i <= m; ++i)
            {
              for (j = 1; j <= MIN(i, n); ++j)
                U(i, j) = A(i, j);
            }
          /* nag_dorgqr (f08afc):                              */
          /*        Form Q explicitly, storing the result in U */
          nag_dorgqr(order, m, m, n, u, pdu, tau, &fail);
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout, "order=%d\n", order);
              fprintf(fpout, "Error from nag_dorgqr (f08afc).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }
          /* Copy R to PT (used as workspace) */
          nag_dtr_copy(order, Nag_Upper, Nag_NoTrans, Nag_NonUnitDiag, n, a,
                       pda, pt, pdpt, &fail);
          /* Set the strictly lower triangular part of R to zero */
          for (i = 2; i <= n; ++i)
            {
              for (j = 1; j <= MIN(i - 1, n - 1); ++j)
                PT(i, j) = 0.0;
            }
          /* nag_dgebrd (f08kec): Bidiagonalize R. */
          nag_dgebrd(order, n, n, pt, pdpt, 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;
            }
          /* nag_dormbr (f08kgc): Update Q, storing the result in U. */
          nag_dormbr(order, Nag_FormQ, Nag_RightSide, Nag_NoTrans,
                     m, n, n, pt, pdpt, tauq, u, pdu, &fail);
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout, "Error from nag_dormbr (f08kgc).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }
          /* Print bidiagonal form and matrix Q */
          fprintf(fpout, "\nExample 1: bidiagonal matrix B\nDiagonal\n");
          for (i = 1; i <= n; ++i)
            fprintf(fpout, "%8.4f%s", d[i - 1], i % 8 == 0?"\n":" ");
          fprintf(fpout, "\nSuper-diagonal\n");
          for (i = 1; i <= n - 1; ++i)
            fprintf(fpout, "%8.4f%s", e[i - 1], i % 8 == 0?"\n":" ");
          fprintf(fpout, "\n\n");
          /* nag_gen_real_mat_print (x04cac): Print Q as stored in u. */
          if (outfile) fclose(fpout);
          nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag,
                                 m, n, u, pdu, "Example 1: matrix Q",
                                 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. */

          /* nag_dgelqf (f08ahc): Compute the LQ factorization of A. */
          nag_dgelqf(order, m, n, a, pda, tau, &fail);
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout, "Error from nag_dgelqf (f08ahc).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }
          /* Copy A to PT */
          for (i = 1; i <= m; ++i)
            {
              for (j = i; j <= n; ++j)
                PT(i, j) = A(i, j);
            }
          /* nag_dorglq (f08ajc):                               */
          /*       Form Q explicitly, storing the result in PT. */
          nag_dorglq(order, n, n, m, pt, pdpt, tau, &fail);
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout, "Error from nag_dorglq (f08ajc).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }
          /* Copy L to U (used as workspace) */
          nag_dtr_copy(order, Nag_Lower, Nag_NoTrans, Nag_NonUnitDiag, m, a,
                       pda, u, pdu, &fail);
          /* Set the strictly upper triangular part of L to zero */
          for (i = 1; i <= m - 1; ++i)
            {
              for (j = i + 1; j <= m; ++j)
                U(i, j) = 0.0;
            }
          /* nag_dgebrd (f08kec): Bidiagonalize L. */
          nag_dgebrd(order, m, m, u, pdu, 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;
            }
          /* nag_dormbr (f08kgc):Update P**T, storing the result in PT. */
          nag_dormbr(order, Nag_FormP, Nag_LeftSide, Nag_Trans, m, n, m, u,
                     pdu, taup, pt, pdpt, &fail);
          if (fail.code != NE_NOERROR)
            {
              fprintf(fpout, "Error from nag_dormbr (f08kgc).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }

          /* Print bidiagonal form and matrix P**T */
          fprintf(fpout, "\nExample 2: bidiagonal matrix B\n%s\n",
                  "Diagonal\n");
          for (i = 1; i <= m; ++i)
            fprintf(fpout, "%8.4f%s", d[i - 1], i % 8 == 0?"\n":" ");
          fprintf(fpout, "\nSuper-diagonal\n");
          for (i = 1; i <= m - 1; ++i)
            fprintf(fpout, "%8.4f%s", e[i - 1], i % 8 == 0?"\n":" ");
          fprintf(fpout, "\n\n");

          /* nag_gen_real_mat_print (x04cac), Print pt. */
          if (outfile) fclose(fpout);
          nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag,
                                 m, n, pt, pdpt, "Example 2: matrix P**T",
                                 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 (d) NAG_FREE(d);
      if (e) NAG_FREE(e);
      if (pt) NAG_FREE(pt);
      if (tau) NAG_FREE(tau);
      if (taup) NAG_FREE(taup);
      if (tauq) NAG_FREE(tauq);
      if (u) NAG_FREE(u);
    }
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  return exit_status;
}
#undef A
#undef U
#undef PT