Discussing tests in Stan math

[martinmodrak]

@Bob_Carpenter

To really get traction on this, it should be automated to allow us to plug in two functions and a range of values and make sure all derivatives have the same value.

This would IMHO be a highly useful tool.

@Bob_Carpenter

The problem I have is that I can’t read that Mathematica code. So the discussion we should have is whether everyone’s OK introducing one more language into the project after OCaml and C++.

We already have a bunch of precomputed values lying around individual tests and nobody is worried that there is no code to recompute them, so having some code is IMHO a strict improvement. But I understand the concern and especially if we ended up building substantial support infrastructure in Mathematica, this might eventually become an issue.