From 020c0c306fcff9355206fe1c02f41ec8bfb9476b Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Mon, 22 Jul 2019 10:10:53 -0500
Subject: [PATCH] Fix bug in delayed group index in MG mode tallies

---
 src/mgxs.cpp                                  |  2 +-
 src/mgxs_interface.cpp                        | 20 ++-----------------
 .../mg_tallies/results_true.dat               |  2 +-
 3 files changed, 4 insertions(+), 20 deletions(-)

diff --git a/src/mgxs.cpp b/src/mgxs.cpp
index 3aac41f35..1fca66308 100644
--- a/src/mgxs.cpp
+++ b/src/mgxs.cpp
@@ -522,7 +522,7 @@ Mgxs::get_xs(int xstype, int gin, const int* gout, const double* mu,
     break;
   case MG_GET_XS_DECAY_RATE:
     if (dg != nullptr) {
-      val = xs_t->decay_rate(a, *dg + 1);
+      val = xs_t->decay_rate(a, *dg);
     } else {
       val = xs_t->decay_rate(a, 0);
     }
diff --git a/src/mgxs_interface.cpp b/src/mgxs_interface.cpp
index c30850e8f..29e5e8b36 100644
--- a/src/mgxs_interface.cpp
+++ b/src/mgxs_interface.cpp
@@ -263,21 +263,13 @@ get_nuclide_xs(int index, int xstype, int gin, const int* gout,
 {
   int gout_c;
   const int* gout_c_p;
-  int dg_c;
-  const int* dg_c_p;
   if (gout != nullptr) {
     gout_c = *gout - 1;
     gout_c_p = &gout_c;
   } else {
     gout_c_p = gout;
   }
-  if (dg != nullptr) {
-    dg_c = *dg - 1;
-    dg_c_p = &dg_c;
-  } else {
-    dg_c_p = dg;
-  }
-  return data::nuclides_MG[index].get_xs(xstype, gin - 1, gout_c_p, mu, dg_c_p);
+  return data::nuclides_MG[index].get_xs(xstype, gin - 1, gout_c_p, mu, dg);
 }
 
 //==============================================================================
@@ -288,21 +280,13 @@ get_macro_xs(int index, int xstype, int gin, const int* gout,
 {
   int gout_c;
   const int* gout_c_p;
-  int dg_c;
-  const int* dg_c_p;
   if (gout != nullptr) {
     gout_c = *gout - 1;
     gout_c_p = &gout_c;
   } else {
     gout_c_p = gout;
   }
-  if (dg != nullptr) {
-    dg_c = *dg - 1;
-    dg_c_p = &dg_c;
-  } else {
-    dg_c_p = dg;
-  }
-  return data::macro_xs[index].get_xs(xstype, gin - 1, gout_c_p, mu, dg_c_p);
+  return data::macro_xs[index].get_xs(xstype, gin - 1, gout_c_p, mu, dg);
 }
 
 //==============================================================================
diff --git a/tests/regression_tests/mg_tallies/results_true.dat b/tests/regression_tests/mg_tallies/results_true.dat
index bc2393f73..50ec653e2 100644
--- a/tests/regression_tests/mg_tallies/results_true.dat
+++ b/tests/regression_tests/mg_tallies/results_true.dat
@@ -1 +1 @@
-15e00a46742e973d7c3c5defe427e6f76a4f1b661538cf54957712751410218dc64301fe12ccb8dbed3f2d51d19b3e99d2b615a3e98c46f9954894e96667dc23
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+508cd056f2d9409a536e487512df34c683720ea45b9100316efb31c19927890c4cacd92f38817d74fcf491bbe4bdb78a0215a798d5a078e0575e3fd94cedf0bd
\ No newline at end of file