compute force matrix from positions matrix

Hi,

I have the following problem. I want to create a function which takes as inputs a 1XN vector of masses and a Nx3 matrix of positions. The k-th row is the coordinates (x,y,z) of the k-th particle. The function should output a Nx3 matrix where the k-th row consists of the cartesian coordinates of the total gravitational force exerted upon the k-th particle.

This is very easy to achive by using loops in the function, but I was wondering whether there is some brief and more eficient way to do this without using any iteration loops.

Thank you for your help!

Answer 1

[Jos (10584)]

There surely is way to vectorise your code, using bsxfun, accumarray and/or arrayfun, for instance. However, this most likely to make your code less efficient and readable.