Merge pull request #2777 from nicolossus/port_test_multiple_random_so…

…urce_stepping

Port `test_multiple_random_source_stepping` from SLI-2-Py

testsuite/pytests/sli2py_other/test_multiple_random_source_stepping.py

@@ -0,0 +1,70 @@
+# -*- coding: utf-8 -*-
+#
+# test_multiple_random_source_stepping.py
+#
+# This file is part of NEST.
+#
+# Copyright (C) 2004 The NEST Initiative
+#
+# NEST is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# NEST is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with NEST.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+Test NEST's behavior when using multiple random sources and different stepping schemes.
+
+The test checks whether simulations of a network with more than one node
+consuming random numbers creates identical output under different stepping
+regimes, e.g., 1x10.0ms vs 100x0.1ms.
+
+.. note::
+    This test works well only if the stepping interval is a multiple of the
+    minimal delay. Otherwise, random numbers will be fed to consumers in
+    different orders, as nodes are updated for parts of minimal delay periods
+    only.
+"""
+
+import numpy.testing as nptest
+
+import nest
+
+
+def run_sim(interval, steppings):
+    """Single simulation run."""
+
+    nest.ResetKernel()
+
+    pg1 = nest.Create("poisson_generator_ps", {"rate": 1000.0})
+    pg2 = nest.Create("poisson_generator_ps", {"rate": 1000.0})
+    sr1 = nest.Create("spike_recorder")
+    sr2 = nest.Create("spike_recorder")
+    nest.Connect(pg1, sr1)
+    nest.Connect(pg2, sr2)
+
+    for _ in range(steppings):
+        nest.Simulate(interval)
+
+    st1 = sr1.events["times"]
+    st2 = sr2.events["times"]
+
+    return st1, st2
+
+
+def test_multiple_random_source_stepping():
+    st1_ref, st2_ref = run_sim(10.0, 1)
+    st1_run1, st2_run1 = run_sim(5.0, 2)
+    st1_run2, st2_run2 = run_sim(1.0, 10)
+
+    nptest.assert_array_equal(st1_run1, st1_ref)
+    nptest.assert_array_equal(st2_run1, st2_ref)
+    nptest.assert_array_equal(st1_run2, st1_ref)
+    nptest.assert_array_equal(st2_run2, st2_ref)