pseudo code

HOLOG

FOR each antenna and ddi
    calculate coordinates in l, m
        IF channel average
	    compute channel averaged mesh grid
	ELSE
	    compute mesh grid
	END IF
            FOR each mapping index
		IF channel average
		    compute visibility weighted sum
		    scale data be frequency
		    grid data
	       ELSE
	            grid data
	       END IF
	    END FOR
		normalize data by XX and YY peaks
		parallactic de-rotation
		calculate aperture pattern

		IF phase correction
		    apply phase correction
		END IF
END FOR
write holog output