diff --git a/contrib/meshgen11_dealii/CMakeLists.txt b/contrib/meshgen11_dealii/CMakeLists.txt
index 2c8f2f2f4b31150fafb21bdbfb0a47f7c89e3384..b7c9ea92ec7f201ec81e7b0e7109cbb65043027a 100644
--- a/contrib/meshgen11_dealii/CMakeLists.txt
+++ b/contrib/meshgen11_dealii/CMakeLists.txt
@@ -69,7 +69,7 @@ else()
     COMPILE_FLAGS "${DEAL_II_CXX_FLAGS} ${DEAL_II_CXX_FLAGS_${_build}}"
     )
   SET_PROPERTY(TARGET meshgen11 APPEND_STRING PROPERTY
-    LINK_FLAGS " ${DEAL_II_LINKER_FLAGS} ${DEAL_II_LINKER_FLAGS_${_build}}"
+    LINK_FLAGS " ${DEAL_II_LINKER_FLAGS} ${DEAL_II_LINKER_FLAGS_${_build}} $ENV{DEAL_II_LINKER_FLAGS}"
     )
   SET_PROPERTY(TARGET meshgen11 APPEND PROPERTY
     COMPILE_DEFINITIONS "${DEAL_II_USER_DEFINITIONS};${DEAL_II_USER_DEFINITIONS_${_build}}"
diff --git a/contrib/meshgen11_dealii/meshgen.cpp b/contrib/meshgen11_dealii/meshgen.cpp
index b7cdcef2fd7f9c9ee51364a1e1aae28e4de5a5b8..90289920ea5f2fbbe3d61a71f08a9356d734f66e 100644
--- a/contrib/meshgen11_dealii/meshgen.cpp
+++ b/contrib/meshgen11_dealii/meshgen.cpp
@@ -145,9 +145,9 @@ public:
     d::GridGenerator::hyper_cube(triangulation, box_a, box_b);
 
     // initial number of levels must be compatible
-    assert(level > self.min_grid_level);
-    assert(level <= self.max_grid_level + 1);
-    assert(std::pow(std::pow(2, dimension), level - 1) <= self.max_n_cells);
+    assert(level > min_grid_level);
+    assert(level <= max_grid_level + 1);
+    assert(std::pow(std::pow(2, dimension), level - 1) <= max_n_cells);
 
     if (level > 1) {
       triangulation.refine_global(level - 1);
@@ -168,9 +168,9 @@ public:
     d::GridGenerator::hyper_cube(triangulation, box_a, box_b);
 
     // initial number of levels must be compatible
-    assert(level > self.min_grid_level);
-    assert(level <= self.max_grid_level + 1);
-    assert(std::pow(std::pow(2, dimension), level - 1) <= self.max_n_cells);
+    assert(level > min_grid_level);
+    assert(level <= max_grid_level + 1);
+    assert(std::pow(std::pow(2, dimension), level - 1) <= max_n_cells);
 
     if (level > 1) {
       triangulation.refine_global(level - 1);
diff --git a/examples/volume_potential_2d.py b/examples/volume_potential_2d.py
index 5eed2addfc66c2e1401fc89f70273b9ebb65d281..9fa3476deed99c80ab3de35fce50a238934c2ee1 100644
--- a/examples/volume_potential_2d.py
+++ b/examples/volume_potential_2d.py
@@ -29,7 +29,7 @@ import logging
 
 logger = logging.getLogger(__name__)
 
-if 0:
+if 1:
     # verbose
     logging.basicConfig(level=logging.INFO)
 else:
@@ -322,7 +322,7 @@ def main():
     import time
     queue.finish()
 
-    t0 = time.clock()
+    t0 = time.process_time()
 
     pot, = drive_volume_fmm(
         trav,
@@ -333,7 +333,7 @@ def main():
     )
     queue.finish()
 
-    t1 = time.clock()
+    t1 = time.process_time()
 
     print("Finished in %.2f seconds." % (t1 - t0))
     print("(%e points per second)" % (
diff --git a/examples/volume_potential_3d.py b/examples/volume_potential_3d.py
index 2997e85b7cbe6fb323f85ff67d25c528f2badb32..3317e42d5f85787291534172cd99cb51d002741c 100644
--- a/examples/volume_potential_3d.py
+++ b/examples/volume_potential_3d.py
@@ -334,7 +334,7 @@ def main():
     import time
     queue.finish()
 
-    t0 = time.clock()
+    t0 = time.process_time()
 
     pot, = drive_volume_fmm(
         trav,
@@ -344,7 +344,7 @@ def main():
         direct_evaluation=force_direct_evaluation,
         list1_only=False)
 
-    t1 = time.clock()
+    t1 = time.process_time()
 
     print("Finished in %.2f seconds." % (t1 - t0))
     print("(%e points per second)" % (
diff --git a/test/test_singular_integral_2d.py b/test/test_singular_integral_2d.py
index 09dcf9d5f0da3adbd2f6de362bfd29c03b98db8c..59d905130080f5335ff2a645064188608efd8d1a 100644
--- a/test/test_singular_integral_2d.py
+++ b/test/test_singular_integral_2d.py
@@ -69,7 +69,7 @@ def test_quadrature_2d_box():
 def test_affine_mapping():
     tria1 = ((1, 1), (2, 3), (0, 4))
     tria2 = ((0, 0), (1, 0), (0, 1))
-    mp, J, imp, iJ = sint.solve_affine_map_2d(tria1, tria2)
+    mp, J, imp, iJ = sint.solve_affine_map_2d(tria1, tria2)  # noqa: N806
     assert np.isclose(J * iJ, 1)
     for i in range(3):
         assert np.allclose(mp(tria1[i]), tria2[i])
@@ -99,7 +99,7 @@ def test_is_in_r():
 
 
 def test_tria2rect_map():
-    t2r, J_t2r, r2t, J_r2t = sint.tria2rect_map_2d()
+    t2r, J_t2r, r2t, J_r2t = sint.tria2rect_map_2d()  # noqa: N806
     assert np.allclose(t2r((0, 0)), (0, 0))
     assert np.allclose(t2r((1, 0)), (1, 0))
     assert np.allclose(t2r((0, 1)), (1, np.pi / 2))
@@ -110,7 +110,7 @@ def test_tria2rect_map():
 
 
 def test_tria2rect_jacobian():
-    t2r, J_t2r, r2t, J_r2t = sint.tria2rect_map_2d()
+    t2r, J_t2r, r2t, J_r2t = sint.tria2rect_map_2d()  # noqa: N806
     p1 = (0.1, 0.1)
     assert np.isclose(J_t2r(p1) * J_r2t(t2r(p1)), 1)
     assert np.isclose(J_r2t(p1) * J_t2r(r2t(p1)), 1)
diff --git a/volumential/function_extension.py b/volumential/function_extension.py
index 1612d60542dff04ca789a5a4a4fc7216496c4e3e..00a31ee7209b8c6f58a38e76f03710ffad3f4f1e 100644
--- a/volumential/function_extension.py
+++ b/volumential/function_extension.py
@@ -424,6 +424,7 @@ def compute_biharmonic_extension(queue, target_discr,
     """Biharmoc extension. Currently only support
     interior domains in 2D (i.e., extension is on the exterior).
     """
+    # pylint: disable=invalid-unary-operand-type
     dim = 2
     queue = setup_command_queue(queue=queue)
     qbx_forced_limit = 1