Invert 4x4 matrix - Numerical most stable solution needed

Question

I want to invert a 4x4 matrix. My numbers are stored in fixed-point format (1.15.16 to be exact).

With floating-point arithmetic I usually just build the adjoint matrix

Answer 1

Let me ask a different question: do you definitely need to invert the matrix (call it M), or do you need to use the matrix inverse to solve other equations? (e.g. Mx = b for known M, b) Often there are other ways to do this w/o explicitly needing to calculate the inverse. Or if the matrix M is a function of time & it changes slowly then you could calculate the full inverse once, & there are iterative ways to update it.