Close sub-simulators on close

Also adds a close method to the emulator (for consistency).

Fixes #102

CHANGES.rst

@@ -27,6 +27,12 @@ Release history
 - An error is now raised if
   a learning rule is applied to a non-decoded connection.
 
+**Fixed**
+
+ - Closing ``nengo_loihi.Simulator`` will now close all the inner
+   sub-simulators as well
+   (`#102 <https://github.com/nengo/nengo-loihi/issues/102>`_)
+
 0.3.0 (September 28, 2018)
 ==========================
 

nengo_loihi/loihi_cx.py

@@ -554,6 +554,7 @@ def __init__(self, model, seed=None):
 
         self._probe_filters = {}
         self._probe_filter_pos = {}
+        self.closed = False
 
     @classmethod
     def error(cls, msg):
@@ -841,3 +842,6 @@ def get_probe_output(self, probe):
         x = np.asarray(self.probe_outputs[cx_probe], dtype=np.float32)
         x = x if cx_probe.weights is None else np.dot(x, cx_probe.weights)
         return self._filter_probe(cx_probe, x)
+
+    def close(self):
+        self.closed = True

nengo_loihi/simulator.py

@@ -305,6 +305,17 @@ def close(self):
         `.Simulator.step`, and `.Simulator.reset` on a closed simulator raises
         a ``SimulatorClosed`` exception.
         """
+
+        if self.loihi is not None:
+            self.loihi.close()
+        if self.simulator is not None:
+            self.simulator.close()
+        if self.precompute:
+            self.host_pre_sim.close()
+            self.host_post_sim.close()
+        else:
+            self.host_sim.close()
+
         self.closed = True
 
     def _probe(self):

nengo_loihi/tests/test_simulator.py

@@ -122,3 +122,27 @@ def test_nengo_comm_channel_compare(simtype, Simulator, seed, plt, allclose):
 
     assert allclose(loihi_sim.data[ap], nengo_sim.data[ap], atol=0.1, rtol=0.2)
     assert allclose(loihi_sim.data[bp], nengo_sim.data[bp], atol=0.1, rtol=0.2)
+
+
+@pytest.mark.parametrize("precompute", (True, False))
+def test_close(Simulator, precompute, pytestconfig):
+    with nengo.Network() as net:
+        a = nengo.Node([0])
+        b = nengo.Ensemble(10, 1)
+        c = nengo.Node(size_in=1)
+        nengo.Connection(a, b)
+        nengo.Connection(b, c)
+
+    with Simulator(net, precompute=precompute) as sim:
+        pass
+
+    assert sim.closed
+    if pytestconfig.getoption("--target") == "loihi":
+        assert sim.loihi.closed
+    else:
+        assert sim.simulator.closed
+    if precompute:
+        assert sim.host_pre_sim.closed
+        assert sim.host_post_sim.closed
+    else:
+        assert sim.host_sim.closed