Diffraction pattern Through several Slits

Is there any available code for diffraction of beam (light)through multiple slits?

I found a link which can simulate double slits experiment (Young's experiment) but I cannot find a way to put several slits in the way of beam:

http://www.mathworks.com/help/distcomp/examples/using-fft2-on-the-gpu-to-simulate-diffraction-patterns.html

Answer 1

[Image Analyst]

You can find the equation here: http://www.ualberta.ca/~pogosyan/teaching/PHYS_130/FALL_2010/lectures/lect36/lecture36.html It shouldn't be tough at all to program that equation into MATLAB.