/* nag_sum_sqs_combine (g02bzc) Example Program.
 *
 * Copyright 2014 Numerical Algorithms Group.
 *
 * Mark 24, 2013.
 */

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

#define X(I,J) x[(order == Nag_ColMajor) ? (J)*pdx + (I) : (I)*pdx + (J)]

int main(void)
{
  /* Integer scalar and array declarations */
  Integer       b, i, j, ierr, lc, pdx, m, n, iwt;
  Integer       exit_status = 0;

  /* NAG structures and types */
  NagError      fail;
  Nag_SumSquare mean;
  Nag_OrderType order = Nag_ColMajor;

  /* Double scalar and array declarations */
  double        alpha, xsw, ysw;
  double        *wt = 0, *x = 0, *xc = 0, *xmean = 0, *yc = 0, *ymean = 0;

  /* Character scalar and array declarations */
  char          cmean[40];

  /* Initialise the error structure */
  INIT_FAIL(fail);

  printf("nag_sum_sqs_combine (g02bzc) Example Program Results\n\n");

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

  /* Read in the problem defining variables */
  scanf("%39s%ld%*[^\n] ",cmean,&m);
  mean = (Nag_SumSquare) nag_enum_name_to_value(cmean);

  /* Allocate memory for output arrays */
  lc = (m*m+m)/2;
  if (!(xmean = NAG_ALLOC(m,  double)) ||
      !(ymean = NAG_ALLOC(m,  double)) ||
      !(xc    = NAG_ALLOC(lc, double)) ||
      !(yc    = NAG_ALLOC(lc, double)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* Loop over each block of data */
  for (b = 0;;)
    {
      /* Read in the number of observations in this block and a flag indicating
       * whether weights have been supplied (iwt = 1) or not (iwt = 0).
       */
      ierr = scanf("%ld%ld",&n,&iwt);

      if (ierr == EOF || ierr < 2) break;
      scanf("%*[^\n] ");

      /* Keep a running total of the number of blocks of data */
      b++;

      /* Reallocate X to the required size */
      NAG_FREE(x);
      pdx = n;
      if (!(x = NAG_ALLOC(pdx*m, double)))
        {
          printf("Allocation failure\n");
          exit_status = -1;
          goto END;
        }

      /* Read in the data for this block */
      if (iwt) {
        /* Weights supplied, so reallocate X to the required size */
        NAG_FREE(wt);
        if (!(wt = NAG_ALLOC(n, double))) {
          printf("Allocation failure\n");
          exit_status = -1;
          goto END;
        }
        for (i = 0; i < n; i++) {
          for (j = 0; j < m; j++)
          scanf("%lf",&X(i,j));
          scanf("%lf",&wt[i]);
        }
      } else {
        /* No weights */
        NAG_FREE(wt);
        wt = 0;

        for (i = 0; i < n; i++)
          for (j = 0; j < m; j++)
        scanf("%lf",&X(i,j));
      }
      scanf("%*[^\n] ");

      /* Call nag_sum_sqs (g02buc) to summarise this block of data */
      if (b == 1) {
        /* This is the first block of data, so summarise the data into
         * xmean and xc.
         */
        nag_sum_sqs(order,mean,n,m,x,pdx,wt,&xsw,xmean,xc,&fail);
        if (fail.code != NE_NOERROR) {
          printf("Error from nag_sum_sqs (g02buc).\n%s\n", fail.message);
          exit_status = 1;
          goto END;
        }
      } else {
        /* This is not the first block of data, so summarise the data into
         * ymean and yc.
         */
        nag_sum_sqs(order,mean,n,m,x,pdx,wt,&ysw,ymean,yc,&fail);
        if (fail.code != NE_NOERROR) {
          printf("Error from nag_sum_sqs (g02buc).\n%s\n", fail.message);
          exit_status = 1;
          goto END;
        }

        /* Call nag_sum_sqs_combine (g02bzc) to update the running summaries */
        nag_sum_sqs_combine(mean,m,&xsw,xmean,xc,ysw,ymean,yc,&fail);
        if (fail.code != NE_NOERROR) {
          printf("Error from nag_sum_sqs_combine (g02bzc).\n%s\n",
                 fail.message);
          exit_status = 1;
          goto END;
        }
      }
    }
  
  /* Display results */
  printf(" Means\n ");
  for (i = 0; i < m; i++)
    printf("%14.4f",xmean[i]);
  printf("\n\n");
  fflush(stdout);

  /* Call nag_pack_real_mat_print (x04ccc) to print the sums of squares */
  nag_pack_real_mat_print(Nag_ColMajor,Nag_Upper,Nag_NonUnitDiag, m, xc,
                          "Sums of squares and cross-products", NULL, &fail);

  if (xsw>1.0 && mean==Nag_AboutMean && fail.code == NE_NOERROR) {
      /* Convert the sums of squares and cross-products to a
         covariance matrix */
      alpha = 1.0/(xsw-1.0);
      for (i = 0; i < lc; i++)
        xc[i] *= alpha;

      printf("\n");
      fflush(stdout);
      nag_pack_real_mat_print(Nag_ColMajor,Nag_Upper,Nag_NonUnitDiag, m, xc,
                              "Covariance matrix", NULL, &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;
  }

 END:
  NAG_FREE(x);
  NAG_FREE(wt);
  NAG_FREE(xc);
  NAG_FREE(xmean);
  NAG_FREE(yc);
  NAG_FREE(ymean);

  return(exit_status);
}