num_procs doesn't exist in Matalb R2019b anymore
There is no function
num_procsin Matlab release 2019b
num_procs is used in
default_option_values.m to initialize number of threads for
A possible alternative would be an undocumented Matlab feature:
Undocumented Matlab features are discussed in this old document: http://undocumentedmatlab.com/articles/undocumented-feature-function/ but is still working.