Monthly Math development meeting: 04/16/2020, 10 am EDT

[mitzimorris]

@syclik

@mitzimorris will start a discourse thread discussing the current Makefile issues and how to proceed.

Makefiles and compiler flag `-DSTAN_THREADS` - always on?

following up on discussion during the 4/16 math meeting - there’s currently a problem with the CmdStan makefiles in that the compiler flag -DSTAN_THREADS must have the same value when compiling the model as when compiling the rest of CmdStan and the stan libraries, because the autodiff implementation is different if STAN_THREADS is on or off. If there’s a mismatch, then model compilation will fail with a linker error. Two options: We could change the makefiles so that -DSTAN_THREADS is alw…