2D Simpson's Integrator

Fully vectorised 2D integrator based on the Simpson's method

Fast, fully vectorised version of the Simpson's method for 2D domains. This code avoids the use of any for loops etc. For a given level of accuracy it can be an order of magnitude or more faster than dblquad.

Examples are provided within the code.

Useage:

ans = simp2D('func',xs,xe,ys,ye,NX,NY)

Input parameters:

func - 2D function that accepts vector inputs (otherwise
incorrect results can occur)
xs, xe - x-limits of integration
ys, ye - y-limits of integration
NX - number of integration intervals in the x-direction (should be even)
NY - number of integration intervals in the y-direction (should be even)