/* nag_dggglm (f08zbc) Example Program.
 *
 * Copyright 2008 Numerical Algorithms Group.
 *
 * Mark 9, 2009.
 */

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

int main(int argc, char *argv[])
{
  FILE          *fpin, *fpout;
  /* 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, *d = 0, *x = 0, *y = 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);

  fpin = nag_example_file_io(argc, argv, "-data", NULL);
  fpout = nag_example_file_io(argc, argv, "-results", NULL);
  fprintf(fpout, "nag_dggglm (f08zbc) Example Program Results\n\n");

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

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

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

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

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

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

  /* Solve the weighted least squares problem      */
  /* minimize ||inv(B)*(d - A*x)|| (in the 2-norm) */
  nag_dggglm(order, n, m, p, a, pda, b, pdb, d, x, y, &fail);

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

      /* Print residual vector y = inv(B)*(d - A*x) */
      fprintf(fpout, "\n");
      fprintf(fpout, "%s\n", "Residual vector");
      for (i = 1; i <= p; ++i)
        fprintf(fpout, "%11.2e%s", y[i - 1], i%7 == 0 || i == p?"\n":" ");

      /* Compute and print the square root of the residual sum of */
      /* squares                                                  */
      nag_dge_norm(Nag_ColMajor, Nag_FrobeniusNorm, 1, p, y, 1, &rnorm, &fail);
      if (fail.code != NE_NOERROR)
        {
          fprintf(fpout, "Error from nag_dge_norm (f16rac).\n%s\n",
                  fail.message);
          exit_status = 1;
          goto END;
        }

      fprintf(fpout, "\nSquare root of the residual sum of squares\n");
      fprintf(fpout, "%11.2e\n", rnorm);
    }
  else
    {
      fprintf(fpout, "Error from nag_dggglm (f08zbc).\n%s\n", fail.message);
      exit_status = 1;
    }

 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  if (a) NAG_FREE(a);
  if (b) NAG_FREE(b);
  if (d) NAG_FREE(d);
  if (x) NAG_FREE(x);
  if (y) NAG_FREE(y);

  return exit_status;
}