Fix progress bar for parallel sampling

Author: jucor

pymc/smc/sampling.py

@@ -25,7 +25,7 @@
 import numpy as np
 
 from arviz import InferenceData
-from fastprogress.fastprogress import progress_bar
+from fastprogress.fastprogress import force_console_behavior, progress_bar
 
 import pymc
 
@@ -376,6 +376,8 @@ def _sample_smc_int(
 
 
 def run_chains_parallel(chains, progressbar, to_run, params, random_seed, kernel_kwargs, cores):
+    # fastprogress HTML progress bar does not support multiprocessing
+    _, progress_bar = force_console_behavior()
     pbar = progress_bar((), total=100, display=progressbar)
     pbar.update(0)
     pbars = [pbar] + [None] * (chains - 1)