CrossValidation & co.: set default n_jobs=1 for backwards compat

Author: kernc

Orange/evaluation/testing.py

@@ -85,7 +85,7 @@ def __init__(self, data=None, nmethods=0, *, learners=None, train_data=None,
                  store_data=False, store_models=False,
                  domain=None, actual=None, row_indices=None,
                  predicted=None, probabilities=None,
-                 preprocessor=None, callback=None, n_jobs=-1):
+                 preprocessor=None, callback=None, n_jobs=1):
         """
         Construct an instance with default values: `None` for :obj:`data` and
         :obj:`models`.
@@ -121,7 +121,7 @@ def __init__(self, data=None, nmethods=0, *, learners=None, train_data=None,
             between 0 and 1
         :type callback: callable
         :param n_jobs: The number of processes to parallelize the evaluation
-            on. -1 to parallelize on all but one CPUs (the default). 1 for no
+            on. -1 to parallelize on all but one CPUs. 1 for no
             parallelization.
         :type n_jobs: int
         """

Orange/widgets/evaluate/owtestlearners.py

@@ -380,7 +380,9 @@ def update_progress(finished):
         common_args = dict(
             store_data=True,
             preprocessor=self.preprocessor,
-            callback=update_progress)
+            callback=update_progress,
+            n_jobs=-1,
+        )
         self.setStatusMessage("Running")
 
         with self.progressBar():