diff --git a/python/test/train_test_model_test.py b/python/test/train_test_model_test.py
index cea491d32..cc6e6ce82 100644
--- a/python/test/train_test_model_test.py
+++ b/python/test/train_test_model_test.py
@@ -6,7 +6,8 @@
 from vmaf.config import VmafConfig
 from vmaf.core.train_test_model import TrainTestModel, \
     LibsvmNusvrTrainTestModel, SklearnRandomForestTrainTestModel, \
-    MomentRandomForestTrainTestModel, SklearnExtraTreesTrainTestModel, SklearnLinearRegressionTrainTestModel
+    MomentRandomForestTrainTestModel, SklearnExtraTreesTrainTestModel, \
+    SklearnLinearRegressionTrainTestModel, Logistic5PLRegressionTrainTestModel
 from vmaf.core.noref_feature_extractor import MomentNorefFeatureExtractor
 from vmaf.routine import read_dataset
 from vmaf.tools.misc import import_python_file
@@ -309,6 +310,20 @@ def test_train_predict_extratrees(self):
         result = model.evaluate(xs, ys)
         self.assertAlmostEqual(result['RMSE'], 0.042867322777879642, places=4)
 
+    def test_train_logistic_fit_5PL(self):    
+        xs = Logistic5PLRegressionTrainTestModel.get_xs_from_results(self.features, [0, 1, 2, 3, 4, 5], features=['Moment_noref_feature_1st_score'])
+        ys = Logistic5PLRegressionTrainTestModel.get_ys_from_results(self.features, [0, 1, 2, 3, 4, 5])
+
+        xys = {}
+        xys.update(xs)
+        xys.update(ys)
+        
+        model = Logistic5PLRegressionTrainTestModel({'norm_type': 'clip_0to1'}, None)
+        model.train(xys)
+        result = model.evaluate(xs, ys)
+
+        self.assertAlmostEqual(result['RMSE'], 0.3603374311919728, places=4)
+
 
 class TrainTestModelWithDisYRawVideoExtractorTest(unittest.TestCase):
 
diff --git a/python/vmaf/core/train_test_model.py b/python/vmaf/core/train_test_model.py
index 356fc2c5e..4b8332216 100644
--- a/python/vmaf/core/train_test_model.py
+++ b/python/vmaf/core/train_test_model.py
@@ -740,7 +740,7 @@ def _delete(filename, **more):
             os.remove(filename)
 
     @classmethod
-    def get_xs_from_results(cls, results, indexs=None, aggregate=True):
+    def get_xs_from_results(cls, results, indexs=None, aggregate=True, features=None):
         """
         :param results: list of BasicResult, or pandas.DataFrame
         :param indexs: indices of results to be used
@@ -756,8 +756,11 @@ def get_xs_from_results(cls, results, indexs=None, aggregate=True):
             # or get_ordered_list_scores_key. Instead, just get the sorted keys
             feature_names = results[0].get_ordered_results()
 
-        feature_names = list(feature_names)
-        cls._assert_dimension(feature_names, results)
+        if features is not None:
+            feature_names = [f for f in feature_names if f in features]
+        else:
+            feature_names = list(feature_names)            
+            cls._assert_dimension(feature_names, results)
 
         # collect results into xs
         xs = {}
@@ -1189,10 +1192,9 @@ def _train(cls, model_param, xys_2d, **kwargs):
             del model_param_['num_models']
 
         from scipy.optimize import curve_fit
-
         [[b1, b2, b3, b4, b5], _] = curve_fit(
             lambda x, b1, b2, b3, b4, b5: b1 + (0.5 - 1/(1+np.exp(b2*(x-b3))))+b4*x+b5, 
-            np.ravel(xys_2d[:, 1:]), 
+            np.ravel(xys_2d[:, 1]), 
             np.ravel(xys_2d[:, 0]), 
             p0=0.5 * np.ones((5,)), 
             maxfev=20000
diff --git a/unittest b/unittest
index 6ca06c762..fc36d56d1 100755
--- a/unittest
+++ b/unittest
@@ -1,3 +1,9 @@
 #!/usr/bin/env sh
 
-PYTHONPATH=python python3 -m unittest discover -v -s python/test/ -p '*_test.py'
+if [ -z "$1" ]; then
+    pattern='*_test.py'
+else
+    pattern="$1"
+fi
+
+PYTHONPATH=python python3 -m unittest discover -v -s python/test/ -p $pattern