From c605c33ea1cc2b9fac6ed175f91c09103d2d8bdb Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Tue, 20 Apr 2021 09:41:35 -0500
Subject: [PATCH 1/3] Change CI to use Ubuntu 20.04

---
 .github/workflows/ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 15392cde0e..6b917e5a05 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -23,7 +23,7 @@ env:
 
 jobs:
   main:
-    runs-on: ubuntu-16.04
+    runs-on: ubuntu-20.04
     strategy:
       matrix:
         python-version: [3.8]

From 3e769e05b4c0bdb0b28c157e10b0f20de782c581 Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Fri, 23 Apr 2021 13:26:10 -0500
Subject: [PATCH 2/3] Update MPI alternatives to use MPICH

---
 .github/workflows/ci.yml | 8 ++++++--
 tools/ci/gha-install.sh  | 2 +-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6b917e5a05..1673af5319 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -95,12 +95,16 @@ jobs:
         shell: bash
         run: |
           sudo apt -y update
-          sudo apt install -y libopenmpi-dev \
+          sudo apt install -y libmpich-dev \
                               libnetcdf-dev \
                               libpnetcdf-dev \
                               libhdf5-serial-dev \
-                              libhdf5-openmpi-dev \
+                              libhdf5-mpich-dev \
                               libeigen3-dev
+          sudo update-alternatives --set mpi /usr/bin/mpicc.mpich
+          sudo update-alternatives --set mpirun /usr/bin/mpirun.mpich
+          sudo update-alternatives --set mpi-x86_64-linux-gnu /usr/include/x86_64-linux-gnu/mpich
+
       -
         name: install
         shell: bash
diff --git a/tools/ci/gha-install.sh b/tools/ci/gha-install.sh
index 2ef4ab9925..8c4762e3e4 100755
--- a/tools/ci/gha-install.sh
+++ b/tools/ci/gha-install.sh
@@ -31,7 +31,7 @@ if [[ $MPI == 'y' ]]; then
 
     export CC=mpicc
     export HDF5_MPI=ON
-    export HDF5_DIR=/usr/lib/x86_64-linux-gnu/hdf5/openmpi
+    export HDF5_DIR=/usr/lib/x86_64-linux-gnu/hdf5/mpich
     pip install --no-binary=h5py h5py
 fi
 

From e1c47437bbb42fc308de8790f163c6a0bd276680 Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Mon, 26 Apr 2021 09:22:45 -0500
Subject: [PATCH 3/3] Avoid several Python warnings

---
 openmc/data/function.py      | 2 +-
 openmc/data/multipole.py     | 2 +-
 openmc/mgxs_library.py       | 2 +-
 openmc/stats/multivariate.py | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/openmc/data/function.py b/openmc/data/function.py
index b6da69d174..b5aa2117d3 100644
--- a/openmc/data/function.py
+++ b/openmc/data/function.py
@@ -580,7 +580,7 @@ class Sum(EqualityMixin):
 
 
 class Regions1D(EqualityMixin):
-    """Piecewise composition of multiple functions.
+    r"""Piecewise composition of multiple functions.
 
     This class allows you to create a callable object which is composed
     of multiple other callable objects, each applying to a specific interval
diff --git a/openmc/data/multipole.py b/openmc/data/multipole.py
index 17948d50ce..508c76ac43 100644
--- a/openmc/data/multipole.py
+++ b/openmc/data/multipole.py
@@ -995,7 +995,7 @@ class WindowedMultipole(EqualityMixin):
 
         out.windows = group['windows'][()]
 
-        out.broaden_poly = group['broaden_poly'][...].astype(np.bool)
+        out.broaden_poly = group['broaden_poly'][...].astype(bool)
         if out.broaden_poly.shape[0] != out.windows.shape[0]:
             raise ValueError(err.format('broaden_poly', 'windows'))
 
diff --git a/openmc/mgxs_library.py b/openmc/mgxs_library.py
index 15ad54c43a..00a155142f 100644
--- a/openmc/mgxs_library.py
+++ b/openmc/mgxs_library.py
@@ -2060,7 +2060,7 @@ class XSdata:
                 Np = self.num_polar
                 Na = self.num_azimuthal
 
-            g_out_bounds = np.zeros((Np, Na, G, 2), dtype=np.int)
+            g_out_bounds = np.zeros((Np, Na, G, 2), dtype=int)
             for p in range(Np):
                 for a in range(Na):
                     for g_in in range(G):
diff --git a/openmc/stats/multivariate.py b/openmc/stats/multivariate.py
index 664e760f71..f33427c34d 100644
--- a/openmc/stats/multivariate.py
+++ b/openmc/stats/multivariate.py
@@ -493,7 +493,7 @@ class SphericalIndependent(Spatial):
         return cls(r, theta, phi, origin=origin)
 
 class CylindricalIndependent(Spatial):
-    """Spatial distribution represented in cylindrical coordinates.
+    r"""Spatial distribution represented in cylindrical coordinates.
 
     This distribution allows one to specify coordinates whose :math:`r`,
     :math:`\phi`, and :math:`z` components are sampled independently from