Start the parallel processes with fork rather than spawn on Linux platforms,...

Start the parallel processes with fork rather than spawn on Linux platforms, resulting in a faster startup.

CHANGELOG.md

@@ -7,6 +7,7 @@
 
 ### Changed
 - The `sfhdelayed` module has been extended to optionally include an exponential burst to model the latest episode of star formation. (Médéric Boquien & Barbara Lo Faro)
+- On Linux platforms the method to start the parallel processes has been changed from "spawn" to "fork". This allows for a much faster startup. On other platforms is remains unchanged as Windows does not support "fork" and MacOS is bugged when using "fork", resulting in a free of cigale. (Médéric Boquien)
 
 ### Fixed
 - The histogram bin width was not computed optimally when some models were invalid. (David Corre & Médéric Boquien)

pcigale/__init__.py

@@ -64,8 +64,12 @@ def main():
     # We set the sub processes start method to spawn because it solves
     # deadlocks when a library cannot handle being used on two sides of a
     # forked process. This happens on modern Macs with the Accelerate library
-    # for instance.
-    mp.set_start_method('spawn')
+    # for instance. On Linux we should be pretty safe with a fork, which allows
+    # to start processes much more rapidly.
+    if sys.platform.startswith('linux'):
+        mp.set_start_method('fork')
+    else:
+        mp.set_start_method('spawn')
 
     parser = argparse.ArgumentParser()