public void getGradient(int[] batch, double[] gradient) {
        for (int i=0; i<batch.length; i++) {
            addGradient(i, gradient);
        }
    }
public void getGradient ( int [ ] batch , double [ ] gradient ) { for ( int i = 0 ; i < batch . length ; i ++ ) { addGradient ( i , gradient ) ; } }
Gets the gradient at the current point, computed on the given batch of examples.
@param batch A set of indices indicating the examples over which the gradient should be computed.
@param gradient The output gradient, a vector of partial derivatives.