From 52516663c69cf9c7add01be0458f69cf57c4d497 Mon Sep 17 00:00:00 2001
From: Jingang Liang <liangjg2008@gmail.com>
Date: Tue, 1 Sep 2020 16:06:57 +0800
Subject: [PATCH] vectfit package is not always required

---
 openmc/data/multipole.py | 6 ++++++
 src/wmp.cpp              | 3 ++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/openmc/data/multipole.py b/openmc/data/multipole.py
index 4d4359cc2b..f0ecfe7077 100644
--- a/openmc/data/multipole.py
+++ b/openmc/data/multipole.py
@@ -175,6 +175,9 @@ def _vectfit_xs(energy, ce_xs, mts, rtol=1e-3, atol=1e-5, orders=None,
 
     """
 
+    # import vectfit package: https://github.com/mit-crpg/vectfit
+    import vectfit as vf
+
     ne = energy.size
     nmt = len(mts)
     if ce_xs.shape != (nmt, ne):
@@ -569,6 +572,9 @@ def _windowing(mp_data, rtol=1e-3, atol=1e-5, n_win=None, n_cf=None,
 
     """
 
+    # import vectfit package: https://github.com/mit-crpg/vectfit
+    import vectfit as vf
+
     # unpack multipole data
     name = mp_data["name"]
     awr = mp_data["AWR"]
diff --git a/src/wmp.cpp b/src/wmp.cpp
index 44b346bb4a..60393e9ba7 100644
--- a/src/wmp.cpp
+++ b/src/wmp.cpp
@@ -10,6 +10,7 @@
 #include <fmt/core.h>
 
 #include <cmath>
+#include <algorithm> // for min
 
 namespace openmc {
 
@@ -71,7 +72,7 @@ WindowedMultipole::evaluate(double E, double sqrtkT)
 
   // Locate window containing energy
   int i_window = std::min(windows_.shape()[0] - 1,
-                          (sqrtE - std::sqrt(E_min_)) / spacing_);
+        static_cast<unsigned long>((sqrtE - std::sqrt(E_min_)) / spacing_));
   int startw = windows_(i_window, 0) - 1;
   int endw = windows_(i_window, 1) - 1;