Method set_output_postcallback

src/tests/fftw_transform.h:443–458

	}

	void set_output_postcallback()
	{
		//postcallback user data
		buffer<T> userdata( 	output.number_of_dimensions(),
					output.lengths(),
					output.strides(),
					output.batch_size(),
					output.distance(),
					layout::real ,
					CLFFT_INPLACE
					);
		
		userdata.set_all_to_random_data(_lengths[0], 10);
		
		output *= userdata;
	}

	void set_input_precallback()
	{