Differentiation logger printing duplicates with MPI

[epaillas]

I'm running some BAO chains using emcee with multiple MPI processes. Some parameters are analytically marginalized over, and the logger is printing this line for every MPI process

[000008.12] [ 24/128] 08-18 10:55 Differentiation INFO Varied parameters: ['al0_-3', 'al0_-2', 'al0_-1', 'al0_0', 'al0_1', 'al2_-3', 'al2_-2', 'al2_-1', 'al2_0', 'al2_1']

I'm guessing the mesage is coming from

desilike/desilike/differentiation.py

Line 234 in e42e89c

self.log_info('Varied parameters: {}.'.format(self.varied_params.names()))

which is supposed to only print it for the root process. Not sure why the logger is bypassing this conditional...

[adematti]

Hi, this is because when performing sampling, likelihood evaluations are distributed over MPI processes. Every process get to execute that differentiation part independently on a COMM_SELF (of size 1, so mpicomm.rank is always 0). Would you prefer this not to happen, or were you just wondering why this happened?