From 6ea533a61fb642e19f9baa0ad4b47e94b2f55f76 Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Wed, 25 Jul 2018 14:58:55 -0500
Subject: [PATCH] Add C API function for resetting tally individually

---
 include/openmc.h             |  1 +
 src/tallies/tally_header.F90 | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/include/openmc.h b/include/openmc.h
index 5f778397e6..f211b4930f 100644
--- a/include/openmc.h
+++ b/include/openmc.h
@@ -97,6 +97,7 @@ extern "C" {
   int openmc_tally_get_n_realizations(int32_t index, int32_t* n);
   int openmc_tally_get_nuclides(int32_t index, int** nuclides, int* n);
   int openmc_tally_get_scores(int32_t index, int** scores, int* n);
+  int openmc_tally_reset(int32_t index);
   int openmc_tally_results(int32_t index, double** ptr, int shape_[3]);
   int openmc_tally_set_active(int32_t index, bool active);
   int openmc_tally_set_filters(int32_t index, int n, const int32_t* indices);
diff --git a/src/tallies/tally_header.F90 b/src/tallies/tally_header.F90
index 16c5a87b8c..6442d58009 100644
--- a/src/tallies/tally_header.F90
+++ b/src/tallies/tally_header.F90
@@ -29,6 +29,7 @@ module tally_header
   public :: openmc_tally_get_n_realizations
   public :: openmc_tally_get_nuclides
   public :: openmc_tally_get_scores
+  public :: openmc_tally_reset
   public :: openmc_tally_results
   public :: openmc_tally_set_active
   public :: openmc_tally_set_filters
@@ -608,6 +609,24 @@ contains
   end function openmc_tally_get_scores
 
 
+  function openmc_tally_reset(index) result(err) bind(C)
+    ! Reset tally results and number of realizations
+    integer(C_INT32_T), intent(in), value :: index
+    integer(C_INT) :: err
+
+    if (index >= 1 .and. index <= size(tallies)) then
+      associate (t => tallies(index) % obj)
+        t % n_realizations = 0
+        if (allocated(t % results)) t % results(:, :, :) = ZERO
+        err = 0
+      end associate
+    else
+      err = E_OUT_OF_BOUNDS
+      call set_errmsg('Index in tallies array is out of bounds.')
+    end if
+  end function openmc_tally_reset
+
+
   function openmc_tally_results(index, ptr, shape_) result(err) bind(C)
     ! Returns a pointer to a tally results array along with its shape. This
     ! allows a user to obtain in-memory tally results from Python directly.