public static double info(int counts[]){
  int total=0;
  double x=0;
  for (int j=0; j < counts.length; j++) {
    x-=xlogx(counts[j]);
    total+=counts[j];
  }
  return x + xlogx(total);
}

public static double info ( int counts [ ] ) { int total = 0 ; double x = 0 ; for ( int j = 0 ; j < counts . length ; j ++ ) { x -= xlogx ( counts [ j ] ) ; total += counts [ j ] ; } return x + xlogx ( total ) ; }
computes entropy for an array of integers .
