diff --git a/.circleci/config.yml b/.circleci/config.yml
index e7dc1c13..ae66c8fe 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -48,15 +48,6 @@ jobs:
           command: |
             sudo apt-get install -y libgeos-dev libproj-dev proj-data graphviz
 
-      - run:
-          name: Install llvmlite
-          command: |
-            sudo apt-get install lsb-release wget software-properties-common
-            wget https://apt.llvm.org/llvm.sh
-            chmod +x llvm.sh
-            sudo ./llvm.sh 10
-            ls /usr/bin/llvm*
-
       - run:
           name: Install standard libraries
           command: |
@@ -74,15 +65,6 @@ jobs:
             pip install --no-binary shapely shapely
             pip install cartopy
 
-      - run:
-          name: Install numba, llvmlite
-          command: |
-            python -m venv venv
-            . venv/bin/activate
-            # export LLVM_CONFIG=/usr/local/opt/llvm/bin/llvm-config
-            sudo ln -s /usr/bin/llvm-config-10 /usr/bin/llvm-config
-            pip install llvmlite numba
-
       - run:
           name: install dependencies
           command: |
diff --git a/.travis.yml b/.travis.yml
index 49cc62c2..222d6028 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,12 +17,6 @@ matrix:
 
 before_install:
     - sudo apt-get install libgeos-dev libproj-dev proj-data graphviz libblas-dev liblapack-dev
-    - wget https://apt.llvm.org/llvm.sh
-    - chmod +x llvm.sh
-    - sudo ./llvm.sh 10
-    - ls /usr/bin/llvm*
-    - export LLVM_CONFIG=/usr/bin/llvm-config
-    # - sudo ln -s /usr/bin/llvm-config-10 /usr/bin/llvm-config
     - sudo apt-get -y install graphviz      
 
 install:
diff --git a/_unittests/ut_module/test_SKIP_code_style.py b/_unittests/ut_module/test_SKIP_code_style.py
index 88b779eb..59012fe2 100644
--- a/_unittests/ut_module/test_SKIP_code_style.py
+++ b/_unittests/ut_module/test_SKIP_code_style.py
@@ -16,7 +16,7 @@ def test_style_src(self):
         check_pep8(src_, fLOG=fLOG,
                    pylint_ignore=('C0103', 'C1801', 'R0201', 'R1705', 'W0108', 'W0613',
                                   'W0201', 'W0221', 'E0632', 'R1702', 'W0212', 'W0223',
-                                  'W0107', "R1720"),
+                                  'W0107', "R1720", 'R1732'),
                    skip=["categories_to_integers.py:174: W0640",
                          "E0401: Unable to import 'mlinsights.mlmodel.piecewise_tree_regression_criterion",
                          "setup.py:",
@@ -29,7 +29,8 @@ def test_style_test(self):
         test = os.path.normpath(os.path.join(thi, "..", ))
         check_pep8(test, fLOG=fLOG, neg_pattern="temp_.*",
                    pylint_ignore=('C0103', 'C1801', 'R0201', 'R1705', 'W0108', 'W0613',
-                                  'C0111', 'W0107', 'C0111', 'R1702', 'C0415', "R1720"),
+                                  'C0111', 'W0107', 'C0111', 'R1702', 'C0415', "R1720",
+                                  'R1732'),
                    skip=["Instance of 'tuple' has no",
                          "[E402] module level import",
                          "E0611: No name '_test_criterion_",
diff --git a/mlinsights/mlmodel/_piecewise_tree_regression_common024.pyx b/mlinsights/mlmodel/_piecewise_tree_regression_common024.pyx
index 5c2fd694..01f4c89b 100644
--- a/mlinsights/mlmodel/_piecewise_tree_regression_common024.pyx
+++ b/mlinsights/mlmodel/_piecewise_tree_regression_common024.pyx
@@ -43,6 +43,14 @@ cdef class CommonRegressorCriterion(Criterion):
     def __cinit__(self, const DOUBLE_t[:, ::1] X):
         self.sample_X = X
 
+    def __deepcopy__(self, memo=None):
+        """
+        This does not a copy but mostly creates a new instance
+        of the same criterion initialized with the same data.
+        """
+        inst = self.__class__(self.sample_X)
+        return inst
+
     cdef void _update_weights(self, SIZE_t start, SIZE_t end, SIZE_t old_pos, SIZE_t new_pos) nogil:
         """
         Updates members `weighted_n_right` and `weighted_n_left`