epclust/src/filter.c

   1 #include <stdlib.h>
   2 #include <R.h>
   3 #include <Rinternals.h>
   4 #include <Rmath.h>
   5
   6 #include <stdio.h>
   7
   8 SEXP filter(SEXP cwt_)
   9 {
  10     int L = INTEGER(getAttrib(cwt_, R_DimSymbol))[0],
  11         D = INTEGER(getAttrib(cwt_, R_DimSymbol))[1];
  12     double *cwt = REAL(cwt_);
  13     SEXP R_fcwt;
  14     PROTECT(R_fcwt = allocMatrix(REALSXP, L, D));
  15     double* fcwt = REAL(R_fcwt);
  16
  17     //TODO: coding style is terrible... no time for now.
  18     for (int col=0; col<D; col++)
  19     {
  20         double v1 = cwt[0];
  21         double ma = v1 + cwt[1] + cwt[2];
  22         for (int i=1; i<L-2; i++)
  23         {
  24             fcwt[i] = ma / 3.;
  25             ma = ma - v1 + cwt[i+2];
  26             v1 = cwt[i];
  27         }
  28         fcwt[0] = cwt[0];
  29         fcwt[L-2] = ma / 3.;
  30         fcwt[L-1] = cwt[L-1];
  31         cwt = cwt + L;
  32         fcwt = fcwt + L;
  33     }
  34
  35     UNPROTECT(1);
  36     return R_fcwt;
  37 }