From f52d2ac18cd2a19a3419ad3e52dd00c9b7848deb Mon Sep 17 00:00:00 2001
From: Will Boyd <wbinventor@gmail.com>
Date: Sun, 28 Oct 2018 20:05:57 -0400
Subject: [PATCH] Added pre-defined CASMO energy group structures to
 openmx.mgxs module

---
 openmc/mgxs/groups.py | 62 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/openmc/mgxs/groups.py b/openmc/mgxs/groups.py
index 338bc4b00c..d6e7ca9aa0 100644
--- a/openmc/mgxs/groups.py
+++ b/openmc/mgxs/groups.py
@@ -77,6 +77,68 @@ class EnergyGroups(object):
         cv.check_greater_than('number of group edges', len(edges), 1)
         self._group_edges = np.array(edges)
 
+    @staticmethod
+    def get_energy_groups(name):
+        """Returns one of many commonly used and energy group structures.
+
+        Parameters
+        ----------
+        name : str
+            The name of the energy group structure. Pre-defined structures
+            include "CASMO-X" (where X is 2, 4, 8, 16, 25, 40 or 70).
+
+        Returns
+        -------
+        EnergyGroups
+            The energy group structure 
+
+        """
+
+        if name == "CASMO-2":
+            group_edges = np.array([
+                0., 6.25e-1, 2.e7])
+        elif name == "CASMO-4":
+            group_edges = np.array([
+                0., 6.25e-1, 5.53e3, 8.21e5, 2.e7])
+        elif name == "CASMO-8":
+            group_edges = np.array([
+                0., 5.8e-2, 1.4e-1, 2.8e-1, 6.25e-1, 4., 5.53e3, 8.21e5, 2.e7])
+        elif name == "CASMO-16":
+            group_edges = np.array([
+                0., 3.e-2, 5.8e-2, 1.4e-1, 2.8e-1, 3.5e-1, 6.25e-1, 8.5e-1,
+                9.72e-1, 1.02, 1.097, 1.15, 1.3,  4., 5.53e3, 8.21e5, 2.e7])
+        elif name == "CASMO-25":
+            group_edges = np.array([
+                0., 3.e-2, 5.8e-2, 1.4e-1, 2.8e-1, 3.5e-1, 6.25e-1, 9.72e-1,
+                1.02, 1.097, 1.15, 1.855, 4., 9.877, 1.5968e1, 1.4873e2,
+                5.53e3, 9.118e3, 1.11e5, 5.e5, 8.21e5, 1.353e6, 2.231e6,
+                3.679e6, 6.0655e6, 2.e7])
+        elif name == "CASMO-40":
+            group_edges = np.array([
+                0., 1.5e-2, 3.e-2, 4.2e-2, 5.8e-2, 8.e-2, 1.e-1, 1.4e-1,
+                1.8e-1, 2.2e-1, 2.8e-1, 3.5e-1, 6.25e-1, 8.5e-1, 9.5e-1,
+                9.72e-1, 1.02, 1.097, 1.15, 1.3, 1.5, 1.855, 2.1, 2.6, 3.3, 4.,
+                9.877, 1.5968e1, 2.77e1, 4.8052e1, 1.4873e2, 5.53e3, 9.118e3,
+                1.11e5, 5.e5, 8.21e5, 1.353e6, 2.231e6, 3.679e6, 6.0655e6,
+                2.e7])
+        elif name == "CASMO-70":
+            group_edges = np.array([
+                0., 5.e-3, 1.e-2, 1.5e-2, 2.e-2, 2.5e-2, 3.e-2, 3.5e-2, 4.2e-2,
+                5.e-2, 5.8e-2, 6.7e-2, 8.e-2, 1.e-1, 1.4e-1, 1.8e-1, 2.2e-1,
+                2.5e-1, 2.8e-1, 3.e-1, 3.2e-1, 3.5e-1, 4.e-1, 5.e-1, 6.25e-1,
+                7.8e-1, 8.5e-1, 9.1e-1, 9.5e-1, 9.72e-1, 9.96e-6, 1.02, 1.045,
+                1.071, 1.097, 1.123, 1.15, 1.3, 1.5, 1.855, 2.1, 2.6, 3.3, 4.,
+                9.877, 1.5968e1, 2.77e1, 4.8052e1, 7.5501e1, 1.4873e2,
+                3.6726e2, 9.069e-2, 1.4251e3, 2.2395e3, 3.5191e3, 5.53e3,
+                9.1183e3, 1.503e4, 2.478e4, 4.085e4, 6.734e4, 1.11e5, 1.83e5,
+                3.025e5, 5.e5, 8.21e5, 1.353e6, 2.231e6, 3.679e6, 6.0655e6,
+                2.e7])
+        else:
+            raise ValueError(f"Energy group structure \"{name}\" is not recognized")
+
+        energy_groups = EnergyGroups(group_edges)
+        return energy_groups
+
     def get_group(self, energy):
         """Returns the energy group in which the given energy resides.