get number of cores and memory from OS

os_stats.py

import os
import multiprocessing

# get the number of logical cpu cores
n_cores = os.cpu_count()
n_cores = multiprocessing.cpu_count()

# get total physical memory
# https://stackoverflow.com/questions/22102999/get-total-physical-memory-in-python
# For MacOS, as per user reports, this works with Python 3.7 but not with Python 3.8
mem_bytes = os.sysconf('SC_PAGE_SIZE') * os.sysconf('SC_PHYS_PAGES')
mem_gib = mem_bytes/(1024.**3)  # e.g. 3.74