diff --git a/DAS/simulator.py b/DAS/simulator.py
index dbd1b37..8b79e2c 100644
--- a/DAS/simulator.py
+++ b/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
 
 
diff --git a/config_example.py b/config_example.py
index 1a4db01..248a8e9 100644
--- a/config_example.py
+++ b/config_example.py
@@ -20,6 +20,10 @@ dumpXML = 1
 visualization = 1
 logLevel = logging.INFO
 
+# number of parallel workers. -1: all cores; 1: sequential
+# for more details, see joblib.Parallel
+numJobs = 3
+
 # Number of simulation runs with the same parameters for statistical relevance
 runs = range(10)