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 kronecker.sparse_hessian_times_B_kronecker_C, perfect_foresight_problem and k_order_perturbation
A possible alternative would be an undocumented Matlab feature: feature('numcores')
Undocumented Matlab features are discussed in this old document: http://undocumentedmatlab.com/articles/undocumented-feature-function/ but is still working.