docs: public static void positive( TupleDesc_F64 input , TupleDesc_U8 output ) {
  		double max = 0;
  		for( int i = 0; i < input.size(); i++ ) {
  			double v = input.value[i];
  			if( v > max )
  				max = v;
  		}
  
  		if( max == 0 )
  			max = 1.0;
  
  		for( int i = 0; i < input.size(); i++ ) {
  			output.value[i] = (byte)(255.0*input.value[i]/max);
  		}
  	}