fix issues with logging in parallel execution

For fixing logging issues see
https://stackoverflow.com/questions/58026381/logging-nested-functions-using-joblib-parallel-and-delayed-calls
and https://github.com/joblib/joblib/issues/1017

Signed-off-by: Csaba Kiraly <csaba.kiraly@gmail.com>

DAS/simulator.py

@@ -104,11 +104,12 @@ class Simulator:
     def initLogger(self):
         """It initializes the logger."""
         logger = logging.getLogger("DAS")
-        logger.setLevel(self.logLevel)
-        ch = logging.StreamHandler()
-        ch.setLevel(self.logLevel)
-        ch.setFormatter(CustomFormatter())
-        logger.addHandler(ch)
+        if len(logger.handlers) == 0:
+            logger.setLevel(self.logLevel)
+            ch = logging.StreamHandler()
+            ch.setLevel(self.logLevel)
+            ch.setFormatter(CustomFormatter())
+            logger.addHandler(ch)
         self.logger = logger
 
 

study.py

@@ -8,11 +8,15 @@ from DAS import *
 # Parallel execution:
 # The code currently uses 'joblib' to execute on multiple cores. For other options such as 'ray', see
 # https://stackoverflow.com/questions/9786102/how-do-i-parallelize-a-simple-python-loop
+# For fixing logging issues in parallel execution, see
+# https://stackoverflow.com/questions/58026381/logging-nested-functions-using-joblib-parallel-and-delayed-calls
+# and https://github.com/joblib/joblib/issues/1017
 
 def runOnce(sim, config, shape):
     if not config.deterministic:
         random.seed(datetime.now())
 
+    sim.initLogger()
     sim.resetShape(shape)
     sim.initValidators()
     sim.initNetwork()