Merge pull request #1534 from woozzu/params

Fix StackedBlocks when layers have no _params

Author: lamblin

pylearn2/blocks.py

@@ -131,8 +131,15 @@ def __init__(self, layers):
         super(StackedBlocks, self).__init__()
 
         self._layers = layers
-        # Do not duplicate the parameters if some are shared between layers
-        self._params = set([p for l in self._layers for p in l._params])
+        self._params = set()
+        for l in self._layers:
+            if not hasattr(l, '_params'):
+                self._params = None
+                break
+            else:
+                # Do not duplicate the parameters if some are shared
+                # between layers
+                self._params.update(l._params)
 
     def layers(self):
         """
@@ -242,7 +249,8 @@ def append(self, layer):
         layer : WRITEME
         """
         self._layers.append(layer)
-        self._params.update(layer._params)
+        if self._params is not None:
+            self._params.update(layer._params)
 
     def get_input_space(self):
         """

pylearn2/tests/test_blocks.py

@@ -0,0 +1,29 @@
+"""
+Unit tests for blocks
+"""
+
+from pylearn2.models.autoencoder import Autoencoder
+from pylearn2.blocks import Block, StackedBlocks
+
+
+def test_stackedblocks_with_params():
+    """
+    Test StackedBlocks when all layers have trainable params
+    """
+
+    aes = [Autoencoder(100, 50, 'tanh', 'tanh'),
+           Autoencoder(50, 10, 'tanh', 'tanh')]
+    sb = StackedBlocks(aes)
+    _params = set([p for l in sb._layers for p in l._params])
+
+    assert sb._params == _params
+
+
+def test_stackedblocks_without_params():
+    """
+    Test StackedBlocks when not all layers have trainable params
+    """
+
+    sb = StackedBlocks([Block(), Block()])
+
+    assert sb._params is None