STAN_CPP_OPTIMS not working

[barbara-su]

I set STAN_CPP_OPTIMS to TRUE but the model does not have STAN_CPP_OPTIMS in mod.exe_info()

build stan model

from cmdstanpy import CmdStanModel
import os

os.environ['CXXFLAGS'] = "-O3 -march=native"

cpp_options = {
'STAN_THREADS': 'TRUE',
'STAN_CPP_OPTIMS': 'TRUE',
}

mod = CmdStanModel(stan_file="xxx.stan",
cpp_options=cpp_options,
force_compile=True
)

mod.exe_info()

{'stan_version_major': '2',
'stan_version_minor': '36',
'stan_version_patch': '0',
'STAN_THREADS': 'true',
'STAN_MPI': 'false',
'STAN_OPENCL': 'false',
'STAN_NO_RANGE_CHECKS': 'false',
'STAN_CPP_OPTIMS': 'false'}

[amas0]

Confirmed that this seems to happening even if you bypass cmdstanpy and use cmdstan directly.

Putting STAN_CPP_OPTIMS=true in the make/local seems to still result in STAN_CPP_OPTIMS=false as reported from the model info. So this is likely not an issue in cmdstanpy.

I created stan-dev/cmdstan#1326 to raise the issue there.

Note: it seems like setting STAN_CPP_OPTIMS=true does impact compilation times, so it may be the case that the optimizations are still being included but the flag is not being reported correct in the info. Would recommend testing to see if you can notice a difference in your compilation times/model run times.

[WardBrian]

Thanks for reporting. The lack of output in exe_info() is indeed more of a cmdstan bug, so we will handle it over there