/* nag_dgglse (f08zac) Example Program.
 *
 * Copyright 2008 Numerical Algorithms Group.
 *
 * Mark 9, 2009.
 */

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

int main(void)
{
  /* Scalars */
  double        rnorm;
  Integer       i, j, m, n, p, pda, pdb;
  Integer       exit_status = 0;
  NagError      fail;
  Nag_OrderType order;
  /* Arrays */
  double        *a = 0, *b = 0, *c = 0, *d = 0, *x = 0;

#ifdef NAG_COLUMN_MAJOR
#define A(I, J) a[(J-1)*pda + I - 1]
#define B(I, J) b[(J-1)*pdb + I - 1]
  order = Nag_ColMajor;
#else
#define A(I, J) a[(I-1)*pda + J - 1]
#define B(I, J) b[(I-1)*pdb + J - 1]
  order = Nag_RowMajor;
#endif

  INIT_FAIL(fail);

  printf("nag_dgglse (f08zac) Example Program Results\n\n");

  /* Skip heading in data file */
  scanf("%*[^\n] ");
  scanf("%ld%ld%ld%*[^\n] ", &m, &n, &p);

#ifdef NAG_COLUMN_MAJOR
  pda = m;
  pdb = p;
#else
  pda = n;
  pdb = n;
#endif

  /* Allocate memory */
  if (!(a = NAG_ALLOC(m*n, double)) ||
      !(b = NAG_ALLOC(p*n, double)) ||
      !(c = NAG_ALLOC(m, double)) ||
      !(d = NAG_ALLOC(p, double)) ||
      !(x = NAG_ALLOC(n, double)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

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

  for (i = 1; i <= p; ++i)
    {
      for (j = 1; j <= n; ++j)
        scanf("%lf", &B(i, j));
    }
  scanf("%*[^\n] ");

  for (i = 1; i <= m; ++i)
    scanf("%lf", &c[i - 1]);
  scanf("%*[^\n] ");


  for (i = 1; i <= p; ++i)
    scanf("%lf", &d[i - 1]);
  scanf("%*[^\n] ");

  /* Solve the equality-constrained least-squares problem    */
  /* minimize ||c - A*x|| (in the 2-norm) subject to B*x = D */
  nag_dgglse(order, m, n, p, a, pda, b, pdb, c, d, x, &fail);

  if (fail.code == NE_NOERROR)
    {
      /* Print least-squares solution */
      printf("%s\n", "Constrained least-squares solution");
      for (i = 1; i <= n; ++i)
        printf("%11.4f%s", x[i - 1], i%7 == 0 || i == n?"\n":" ");

      /* Compute the square root of the residual sum of squares */
      nag_dge_norm(Nag_ColMajor, Nag_FrobeniusNorm, 1, m - n + p, &c[n - p], 1,
                   &rnorm, &fail);
      if (fail.code != NE_NOERROR)
        {
          printf("Error from nag_dge_norm (f16rac).\n%s\n",
                  fail.message);
          exit_status = 1;
          goto END;
        }
      printf("\nSquare root of the residual sum of squares\n");
      printf("%11.2e\n", rnorm);
    }
  else
    {
      printf("Error from nag_dgglse (f08zac).\n%s\n", fail.message);
      exit_status = 1;
    }

 END:
  if (a) NAG_FREE(a);
  if (b) NAG_FREE(b);
  if (c) NAG_FREE(c);
  if (d) NAG_FREE(d);
  if (x) NAG_FREE(x);

  return exit_status;
}