DIY-FEA
From EVOCD
Quick Overview
This is for those who wish to create their own numerical solvers, either because the current one you use is sub-optimal (see: [1] ) or you want to test a new idea. The code is a rather useful library of all of the required numerics if you wish to implement your own solver for finite element analysis. It has all fo the basis functions for linear, quadratic, and cubic serendipity elements in both 2D and 3D, as well as code for generating stable high order elements in any dimension and code for making 4D Lagrangian elements for those interested in general relativity calculations.
It can be found at: DIY-FEA