#include <math.h>       /* log */
#include <Rcpp.h>
using namespace Rcpp;

// [[Rcpp::export]]
double LRTrow(IntegerVector x)
{
  LogicalVector z = x>0;
  IntegerVector y = x[z];
  double lrtc = sum(y);
  if (lrtc>0) lrtc = - lrtc*log(lrtc);
  for (int i=1; i<= y.size(); i++) 
    lrtc += y[i-1]*log(y[i-1]);
  return lrtc; 
}

/*** R

LRTrow(c(2,1,0))

 */
