Allow saving with pickle

Author: cknd

pyESN.py

@@ -24,13 +24,17 @@ def correct_dimensions(s, targetlength):
     return s
 
 
+def identity(x):
+    return x
+
+
 class ESN():
 
     def __init__(self, n_inputs, n_outputs, n_reservoir=200,
                  spectral_radius=0.95, sparsity=0, noise=0.001, input_shift=None,
                  input_scaling=None, teacher_forcing=True, feedback_scaling=None,
                  teacher_scaling=None, teacher_shift=None,
-                 out_activation=lambda x: x, inverse_out_activation=lambda x: x,
+                 out_activation=identity, inverse_out_activation=identity,
                  random_state=None, silent=True):
         """
         Args:

testing.py

@@ -58,6 +58,17 @@ def test_nonsense(self):
             ESN(N_in, N_out, random_state=0.5)
         self.assertIn("Invalid seed", str(cm.exception))
 
+    def test_serialisation(self):
+        import pickle
+        import io
+        esn = ESN(N_in, N_out, random_state=1)
+        with io.BytesIO() as buf:
+            pickle.dump(esn, buf)
+            buf.flush()
+            buf.seek(0)
+            esn_unpickled = pickle.load(buf)
+        self._compare(esn, esn_unpickled, should_be='same')
+
 
 class InitArguments(unittest.TestCase):