diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index a401054d..0e4e6ea4 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -28,7 +28,7 @@ jobs:
 
       - name: Build coverage file
         run: |
-          pytest --junitxml=pytest.xml --cov-report=term-missing --cov=choice_learn tests/ | tee pytest-coverage.txt
+          pytest -n auto --junitxml=pytest.xml --cov-report=term-missing --cov=choice_learn tests/ | tee pytest-coverage.txt
           cat pytest-coverage.txt
 
       - name: Pytest coverage comment
diff --git a/choice_learn/models/latent_class_base_model.py b/choice_learn/models/latent_class_base_model.py
index adfd7550..2f9321af 100644
--- a/choice_learn/models/latent_class_base_model.py
+++ b/choice_learn/models/latent_class_base_model.py
@@ -360,7 +360,7 @@ def _lbfgs_train_step(self, choice_dataset, sample_weight=None):
         part = []  # partition indices
 
         for i, shape in enumerate(shapes):
-            n = np.product(shape)
+            n = np.prod(shape)
             idx.append(tf.reshape(tf.range(count, count + n, dtype=tf.int32), shape))
             part.extend([i] * n)
             count += n