From 7f66b4694cc57b728663e15e3f70148c4dfe7bed Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Fri, 15 Sep 2017 14:04:31 -0500
Subject: [PATCH] Get rid of n_active global, allow a few settings to be
 controlled from openmc.capi

---
 openmc/capi/__init__.py |  1 +
 openmc/capi/settings.py | 65 +++++++++++++++++++++++++++++++++++++++++
 src/input_xml.F90       |  5 +---
 src/output.F90          |  2 ++
 src/settings.F90        | 15 +++++-----
 5 files changed, 77 insertions(+), 11 deletions(-)
 create mode 100644 openmc/capi/settings.py

diff --git a/openmc/capi/__init__.py b/openmc/capi/__init__.py
index 1480707577..88a69df341 100644
--- a/openmc/capi/__init__.py
+++ b/openmc/capi/__init__.py
@@ -37,3 +37,4 @@ from .material import *
 from .cell import *
 from .filter import *
 from .tally import *
+from .settings import settings
diff --git a/openmc/capi/settings.py b/openmc/capi/settings.py
new file mode 100644
index 0000000000..40d1768cfd
--- /dev/null
+++ b/openmc/capi/settings.py
@@ -0,0 +1,65 @@
+from ctypes import c_int, c_int32, c_int64, c_double, c_char_p, POINTER
+
+from . import _dll
+from .error import _error_handler
+
+_RUN_MODES = {1: 'fixed source',
+              2: 'eigenvalue',
+              3: 'plot',
+              4: 'particle restart',
+              5: 'volume'}
+
+
+class _Settings(object):
+    @property
+    def batches(self):
+        return c_int32.in_dll(_dll, 'n_batches').value
+
+    @batches.setter
+    def batches(self, n):
+        _dll.openmc_set_batches(n)
+
+    @property
+    def generations_per_batch(self):
+        return c_int32.in_dll(_dll, 'gen_per_batch').value
+
+    @generations_per_batch.setter
+    def generations_per_batch(self, n):
+        _dll.openmc_set_generations_per_batch(n)
+
+    @property
+    def inactive(self):
+        return c_int32.in_dll(_dll, 'n_inactive').value
+
+    @inactive.setter
+    def inactive(self, n):
+        _dll.openmc_set_inactive_batches(n)
+
+    @property
+    def particles(self):
+        return c_int64.in_dll(_dll, 'n_particles').value
+
+    @particles.setter
+    def particles(self, n):
+        _dll.openmc_set_particles(n)
+
+    @property
+    def run_mode(self):
+        i = c_int.in_dll(_dll, 'run_mode').value
+        try:
+            return _RUN_MODES[i]
+        except KeyError:
+            return None
+
+    @run_mode.setter
+    def run_mode(self, mode):
+        current_idx = c_int.in_dll(_dll, 'run_mode')
+        for idx, mode_value in _RUN_MODES.items():
+            if mode_value == mode:
+                current_idx.value = idx
+                break
+        else:
+            raise ValueError('Invalid run mode: {}'.format(mode))
+
+
+settings = _Settings()
diff --git a/src/input_xml.F90 b/src/input_xml.F90
index c7e80fe989..0ef4d2b306 100644
--- a/src/input_xml.F90
+++ b/src/input_xml.F90
@@ -322,7 +322,7 @@ contains
       call get_run_parameters(node_mode)
 
       ! Check number of active batches, inactive batches, and particles
-      if (n_active <= 0) then
+      if (n_batches <= n_inactive) then
         call fatal_error("Number of active batches must be greater than zero.")
       elseif (n_inactive < 0) then
         call fatal_error("Number of inactive batches must be non-negative.")
@@ -891,9 +891,6 @@ contains
       end if
     end if
 
-    ! Determine number of active batches
-    n_active = n_batches - n_inactive
-
   end subroutine get_run_parameters
 
 !===============================================================================
diff --git a/src/output.F90 b/src/output.F90
index 215942bfe6..e3d2b8ac14 100644
--- a/src/output.F90
+++ b/src/output.F90
@@ -532,6 +532,7 @@ contains
 
   subroutine print_runtime()
 
+    integer       :: n_active
     real(8)       :: speed_inactive  ! # of neutrons/second in inactive batches
     real(8)       :: speed_active    ! # of neutrons/second in active batches
     character(15) :: string
@@ -564,6 +565,7 @@ contains
     write(ou,100) "Total time elapsed", time_total % elapsed
 
     ! Calculate particle rate in active/inactive batches
+    n_active = n_batches - n_inactive
     if (restart_run) then
       if (restart_batch < n_inactive) then
         speed_inactive = real(n_particles * (n_inactive - restart_batch) * &
diff --git a/src/settings.F90 b/src/settings.F90
index d1d41a75c7..add7f5b903 100644
--- a/src/settings.F90
+++ b/src/settings.F90
@@ -1,12 +1,14 @@
 module settings
 
+  use, intrinsic :: ISO_C_BINDING
+
   use constants
   use set_header,    only: SetInt
   use source_header
 
   implicit none
 
-    ! ============================================================================
+  ! ============================================================================
   ! ENERGY TREATMENT RELATED VARIABLES
   logical :: run_CE = .true.  ! Run in CE mode?
 
@@ -46,11 +48,10 @@ module settings
   ! ============================================================================
   ! SIMULATION VARIABLES
 
-  integer(8) :: n_particles = 0   ! # of particles per generation
-  integer    :: n_batches         ! # of batches
-  integer    :: n_inactive        ! # of inactive batches
-  integer    :: n_active          ! # of active batches
-  integer    :: gen_per_batch = 1 ! # of generations per batch
+  integer(C_INT64_T), bind(C) :: n_particles = 0   ! # of particles per generation
+  integer(C_INT32_T), bind(C) :: n_batches         ! # of batches
+  integer(C_INT32_T), bind(C) :: n_inactive        ! # of inactive batches
+  integer(C_INT32_T), bind(C) :: gen_per_batch = 1 ! # of generations per batch
 
   integer :: n_max_batches             ! max # of batches
   integer :: n_batch_interval = 1      ! batch interval for triggers
@@ -75,7 +76,7 @@ module settings
   real(8) :: weight_survive = ONE
 
   ! Mode to run in (fixed source, eigenvalue, plotting, etc)
-  integer :: run_mode = NONE
+  integer(C_INT), bind(C) :: run_mode = NONE
 
   ! Restart run
   logical :: restart_run = .false.