From a86c3481d682743cb6d78735a56b6cffd46385c0 Mon Sep 17 00:00:00 2001
From: Andrew Johnson <drewej@protonmail.com>
Date: Sat, 21 Mar 2020 10:15:32 -0400
Subject: [PATCH]  ResultList.get_atoms supports atom densities, days

Two new optional arguments to ResultsList.get_atoms are
introduced that control the units on the return values.
Time can be returned in second or in days if time_units is
"s" or "d", respectively. Concentrations can be returned
in atoms/cm^3 or atoms/b/cm if nuc_units is one of those values.
The default is to return time in seconds and number of atoms,
retaining back compatibility.
---
 openmc/deplete/results_list.py | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/openmc/deplete/results_list.py b/openmc/deplete/results_list.py
index 1b5b81ac4c..9e7cd9ffb9 100644
--- a/openmc/deplete/results_list.py
+++ b/openmc/deplete/results_list.py
@@ -2,7 +2,7 @@ import h5py
 import numpy as np
 
 from .results import Results, _VERSION_RESULTS
-from openmc.checkvalue import check_filetype_version
+from openmc.checkvalue import check_filetype_version, check_value
 
 
 __all__ = ["ResultsList"]
@@ -40,7 +40,7 @@ class ResultsList(list):
                 new.append(Results.from_hdf5(fh, i))
         return new
 
-    def get_atoms(self, mat, nuc):
+    def get_atoms(self, mat, nuc, nuc_units="atoms", time_units="s"):
         """Get number of nuclides over time from a single material
 
         .. note::
@@ -57,15 +57,24 @@ class ResultsList(list):
             Material name to evaluate
         nuc : str
             Nuclide name to evaluate
+        nuc_units : {"atoms", "atoms/b/cm", "atoms/cm^3"}, optional
+            Units for the returned concentration. Default is ``"atoms"``
+        time_units : {"s", "d"}, optional
+            Units for the returned time array. Default is ``"s"`` to
+            return the value in seconds
 
         Returns
         -------
         time : numpy.ndarray
-            Array of times in [s]
+            Array of times in units of ``time_units``
         concentration : numpy.ndarray
-            Total number of atoms for specified nuclide
+            Concentration of specified nuclide in units of ``nuc_units``
 
         """
+        check_value("time_units", time_units, {"s", "d"})
+        check_value("nuc_units", nuc_units,
+                    {"atoms", "atoms/b/cm", "atoms/cm^3"})
+
         time = np.empty_like(self, dtype=float)
         concentration = np.empty_like(self, dtype=float)
 
@@ -74,6 +83,17 @@ class ResultsList(list):
             time[i] = result.time[0]
             concentration[i] = result[0, mat, nuc]
 
+        # Unit conversions
+        if time_units == "d":
+            time /= (60 * 60 * 24)
+
+        if nuc_units != "atoms":
+            # Divide by volume to get density
+            concentration /= self[0].volume[mat]
+            if nuc_units == "atoms/b/cm":
+                # 1 barn = 1e-24 cm^2
+                concentration *= 1e-24
+
         return time, concentration
 
     def get_reaction_rate(self, mat, nuc, rx):