/* nag_sum_sqs_update (g02btc) Example Program.
 *
 * Copyright 2014 Numerical Algorithms Group.
 *
 * Mark 7, 2002.
 */

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nag_string.h>
#include <nagf16.h>
#include <nagg02.h>
#include <nagx04.h>

int main(void)
{
  /* Arrays */
  char          nag_enum_arg[40];
  double        *c = 0, *v = 0, *x = 0, *xbar = 0;
  /* Scalars */
  double        alpha, sw, wt;
  Integer       exit_status, i, j, m, mm, n, nprint, incx;
  Nag_SumSquare mean;
  NagError      fail;

  INIT_FAIL(fail);

  exit_status = 0;
  printf("nag_sum_sqs_update (g02btc) Example Program Results\n");

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

  incx = 1;
  while (scanf("%39s %ld%ld%ld%*[^\n]",
               nag_enum_arg, &m, &n, &nprint) != EOF)
    {
      /* nag_enum_name_to_value (x04nac).
       * Converts NAG enum member name to value
       */
      mean = (Nag_SumSquare) nag_enum_name_to_value(nag_enum_arg);
      /* Allocate memory */
      if (!(c = NAG_ALLOC((m*m+m)/2, double)) ||
          !(v = NAG_ALLOC((m*m+m)/2, double)) ||
          !(x = NAG_ALLOC(m*incx, double)) ||
          !(xbar = NAG_ALLOC(m, double)))
        {
          printf("Allocation failure\n");
          exit_status = -1;
          goto END;
        }

      sw = 0.0;
      for (i = 1; i <= n; ++i)
        {
          scanf("%lf", &wt);
          for (j = 1; j <= m; ++j)
            scanf("%lf", &x[j - 1]);
          scanf("%*[^\n] ");

          /* Calculate the sums of squares and cross-products matrix */
          /* nag_sum_sqs_update (g02btc).
           * Update a weighted sum of squares matrix with a new
           * observation
           */
          nag_sum_sqs_update(mean, m, wt, x, incx, &sw, xbar, c, &fail);

          if (fail.code != NE_NOERROR)
            {
              printf("Error from nag_sum_sqs_update (g02btc).\n%s\n",
                      fail.message);
              exit_status = 1;
              goto END;
            }

          if (i % nprint == 0 || i == n)
            {
              printf("\n");
              printf("---------------------------------------------\n");
              printf("Observation: %4ld      Weight = %13.4f\n",
                      i, wt);
              printf("\n");
              printf("---------------------------------------------\n");
              printf("\n");

              printf("Means\n");
              for (j = 1; j <= m; ++j)
                printf("%14.4f%s", xbar[j - 1],
                        j%4 == 0 || j == m?"\n":" ");
              printf("\n");

              /* Print the sums of squares and cross products matrix */
              /* nag_pack_real_mat_print (x04ccc).
               * Print real packed triangular matrix (easy-to-use)
               */
              fflush(stdout);
              nag_pack_real_mat_print(Nag_ColMajor, Nag_Upper, Nag_NonUnitDiag,
                                      m, c,
                                      "Sums of squares and cross-products",
                                      0, &fail);
              if (fail.code != NE_NOERROR)
                {
                  printf("Error from nag_pack_real_mat_print (x04ccc).\n%s\n",
                         fail.message);
                  exit_status = 1;
                  goto END;
                }
              if (sw > 1.0)
                {
                  /* Calculate the variance matrix */
                  alpha = 1.0 / (sw - 1.0);
                  mm = m * (m + 1) / 2;
                  /* v[] = alpha*c[] using 
                   * nag_daxpby (f16ecc)
                   * Multiply real vector by scalar, preserving input vector
                   */
                  nag_daxpby(mm, alpha, c, 1, 0.0, v, 1, &fail);

                  /* Print the variance matrix */
                  printf("\n");
                  /* nag_pack_real_mat_print (x04ccc), see above. */
                  fflush(stdout);
                  nag_pack_real_mat_print(Nag_ColMajor, Nag_Upper,
                                          Nag_NonUnitDiag, m, v,
                                          "Variance matrix", 0, &fail);
                  if (fail.code != NE_NOERROR)
                    {
                      printf("Error from nag_pack_real_mat_print (x04ccc)."
                             "\n%s\n", fail.message);
                      exit_status = 1;
                      goto END;
                    }
                }
            }
        }

      NAG_FREE(c);
      NAG_FREE(v);
      NAG_FREE(x);
      NAG_FREE(xbar);
    }

 END:
  NAG_FREE(c);
  NAG_FREE(v);
  NAG_FREE(x);
  NAG_FREE(xbar);

  return exit_status;
}