Best CPU for RStan/brms

[andre.pfeuffer]

Speed up is significant as shown here:

Speedup by using external BLAS/LAPACK with CmdStan and CmdStanR/Py

@Bob_Carpenter asked whether the above mentioned flags need to defined when building CmdStan, or is it sufficient to give them only when compiling the model. I tested this, and it is sufficient to define them at the model compilation time. It is not yet completely clear whether there could be speedup, e.g., in $cmdstan_summary() if those options would be used already when building CmdStan. The current CmdStanR documentation did not have an example how to add flags with += in the compile method,…

It’s also important to know the compiler version, operating system and system.
Adding CFLAGS+=-fPIC -O3 -mtune=native -march=native in file make/local
forcing a rebuild if Stan with cmdstand_rebuild() or similar in other environments should be sufficient.