Ok so I need to solve the 2D Poisson's equation using the G-S method. I have my differencing equation and boundary conditions. But for the life of me I can't follow the algorithms on how to write a matlab code for it. My professor seemed to imply that you needed to just take the differencing equation and sweep it over the range of x and y until the tolerance is met. It gives me a nice 3d parabolic shape but the magnitude is way off from what would be expected. On the wiki article for G-S it talks about using an A matrix, but all we have done along those lines was for the Thomas algorithm. And the matrix I get for this case doesn't fit what everyone seems to think it should look like. What should I be doing?