private void init(){
  double normalizedFrequency=(double)mTargetFrequency / mSampleRate;
  mCoefficient=2.0D * Math.cos(2 * Math.PI * normalizedFrequency);
}

private void init ( ) { double normalizedFrequency = ( double ) mTargetFrequency / mSampleRate ; mCoefficient = 2.0D * Math . cos ( 2 * Math . PI * normalizedFrequency ) ; }
establish the pre - calculated values to use in the filter
