From 3b00ed3864d2fabff601f31d67994f4828c0af28 Mon Sep 17 00:00:00 2001
From: Patrick Shriwise <pshriwise@gmail.com>
Date: Thu, 8 Sep 2022 22:37:57 -0500
Subject: [PATCH] Adding checks for data size based on interpolation type

---
 openmc/filter.py | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/openmc/filter.py b/openmc/filter.py
index c1ce573c9a..7a85e2d451 100644
--- a/openmc/filter.py
+++ b/openmc/filter.py
@@ -2058,6 +2058,13 @@ class EnergyFunctionFilter(Filter):
     def interpolation(self, val):
         cv.check_type('interpolation', val, str)
         cv.check_value('interpolation', val, self.INTERPOLATION_SCHEMES.values())
+
+        if val == 'quadratic' and len(self.energy) < 3:
+            raise ValueError('Quadratic interpolation requires 3 or more values.')
+
+        if val == 'cubic' and len(self.energy) < 4:
+            raise ValueError('Cubic interpolation requires 3 or more values.')
+
         self._interpolation = val
 
     def to_xml_element(self):