GPU CI testing


#42

I changed it on our branch. Thanks!


#43

We just merged those fixes to develop… so there will be a minor conflict when you merge in develop now, but that will be an easy one. Now testing should again work reliable on stan math.


#44

@Bob_Carpenter @syclik matrix_gpu branch is passing the tests and ready for review!


#45

Awesome! I hope someone else can handle this one. It’ll be a lot of config and matrix stuff, neither of which are strong points for me.