Add context manager for shared library calls

docs/source/pythonapi/capi.rst

@@ -2,6 +2,13 @@
 :data:`openmc.capi` -- Python bindings to the C API
 ---------------------------------------------------
 
+.. autosummary::
+   :toctree: generated
+   :nosignatures:
+   :template: myfunction.rst
+
+   openmc.capi.lib_context
+
 .. autosummary::
    :toctree: generated
    :nosignatures:

openmc/__init__.py

@@ -27,6 +27,6 @@ from openmc.particle_restart import *
 from openmc.mixin import *
 from openmc.plotter import *
 from openmc.search import *
-from openmc.capi import lib, OpenMCLibrary
+from openmc.capi import *
 
 __version__ = '0.9.0'

openmc/capi.py

@@ -1,3 +1,4 @@
+from contextlib import contextmanager
 from ctypes import CDLL, c_int, c_int32, c_double, c_char_p, POINTER
 import sys
 from warnings import warn
@@ -7,6 +8,8 @@ from numpy.ctypeslib import as_array
 
 import pkg_resources
 
+__all__ = ['OpenMCLibrary', 'lib', 'lib_context']
+
 _int3 = c_int*3
 _double3 = c_double*3
 _double_array = POINTER(POINTER(c_double))
@@ -80,7 +83,6 @@ class OpenMCLibrary(object):
         else:
             return self._dll.openmc_cell_set_temperature(cell_id, T, None)
 
-
     def finalize(self):
         """Finalize simulation and free memory"""
         return self._dll.openmc_finalize()
@@ -124,7 +126,7 @@ class OpenMCLibrary(object):
 
         Parameters
         ----------
-        intracomm : int or None
+        intracomm : mpi4py.MPI.Intracomm or None
             MPI intracommunicator
 
         """
@@ -258,6 +260,32 @@ class OpenMCLibrary(object):
                                  .format(key))
 
 
+@contextmanager
+def lib_context(intracomm=None):
+    """Provides context manager for calling OpenMC shared library functions.
+
+    This function is intended to be used in a 'with' statement and ensures that
+    OpenMC is properly initialized/finalized. At the completion of the 'with'
+    block, all memory that was allocated during the block is freed. For
+    example::
+
+        with openmc.lib_context() as lib:
+            for i in range(n_iters):
+                lib.reset()
+                do_stuff()
+                lib.run()
+
+    Parameters
+    ----------
+    intracomm : mpi4py.MPI.Intracomm or None
+        MPI intracommunicator
+
+    """
+    lib.init(comm)
+    yield lib
+    lib.finalize()
+
+
 # Determine shared-library suffix
 if sys.platform == 'darwin':
     suffix = 'dylib'