added new test cases for coverage

Author: kirschte

keras_contrib/wrappers/__init__.py

@@ -1,3 +1,3 @@
 from __future__ import absolute_import
 
-from .cdropout import ConcreteDropout
+from .cdropout import ConcreteDropout

keras_contrib/wrappers/cdropout.py

@@ -2,10 +2,9 @@
 from __future__ import absolute_import
 
 import numpy as np
-
 from keras import backend as K
-from keras.engine import InputSpec
 from keras.initializers import RandomUniform
+from keras.layers import InputSpec
 from keras.layers.wrappers import Wrapper
 
 
@@ -34,7 +33,7 @@ class ConcreteDropout(Wrapper):
         model_precision: float. Model precision parameter is `1` for classification.
                          Also known as inverse observation noise.
         prob_init: Tuple[float, float].
-                   Probability  lower / upper bounds of dropout rate initialization.
+                   Probability lower / upper bounds of dropout rate initialization.
         temp: float. Temperature. Not used to be optimized.
         seed: Seed for random probability  sampling.
 
@@ -156,7 +155,7 @@ def relaxed_dropped_inputs():
     def get_config(self):
         config = {'weight_regularizer': self.weight_regularizer,
                   'dropout_regularizer': self.dropout_regularizer,
-                  'prob_init': self.prob_init,
+                  'prob_init': tuple(np.round(self.prob_init, 8)),
                   'temp': self.temp,
                   'seed': self.seed}
         base_config = super(ConcreteDropout, self).get_config()

tests/keras_contrib/wrappers/test_cdropout.py

@@ -1,13 +1,12 @@
 import pytest
 import numpy as np
 
-from keras.layers import Input, Dense
-from keras.models import Model
 from numpy.testing import assert_allclose
 from numpy.testing import assert_array_almost_equal
 from numpy.testing import assert_approx_equal
 from numpy.testing import assert_equal
-
+from keras.layers import Input, Dense, Conv2D, Conv1D
+from keras.models import Model
 from keras_contrib.wrappers import ConcreteDropout
 
 
@@ -20,7 +19,7 @@ def test_cdropout():
 
     #  Model
     inputs = Input(shape=(in_dim,))
-    dense = Dense(1, use_bias=True, input_shape=(in_dim,))
+    dense = Dense(1, use_bias=True)
     #  Model, normal
     cd = ConcreteDropout(dense, in_dim, prob_init=(init_prop, init_prop))
     x = cd(inputs)
@@ -55,5 +54,61 @@ def sigmoid(x):
     assert_approx_equal(eval_loss, loss)
 
 
+def test_cdropout_conv():
+    #  Data
+    in_dim = 20
+    init_prop = .1
+    np.random.seed(1)
+    X = np.random.randn(1, in_dim, in_dim, 1)
+
+    #  Model
+    inputs = Input(shape=(in_dim, in_dim, 1,))
+    conv2d = Conv2D(1, (3, 3))
+    #  Model, normal
+    cd = ConcreteDropout(conv2d, in_dim, prob_init=(init_prop, init_prop))
+    x = cd(inputs)
+    model = Model(inputs, x)
+    model.compile(loss=None, optimizer='rmsprop')
+    #  Model, reference w/o Dropout
+    x_ref = conv2d(inputs)
+    model_ref = Model(inputs, x_ref)
+    model_ref.compile(loss=None, optimizer='rmsprop')
+
+    #  Check about correct 3rd weight (equal to initial value)
+    W = model.get_weights()
+    assert_array_almost_equal(W[2], [np.log(init_prop)])
+
+    #  Check if ConcreteDropout in prediction phase is the same as no dropout
+    out = model.predict(X)
+    out_ref = model_ref.predict(X)
+    assert_allclose(out, out_ref, atol=1e-5)
+
+    #  Check if ConcreteDropout has the right amount of losses deposited
+    assert_equal(len(model.losses), 1)
+
+    #  Check if the loss correspons the the desired value
+    def sigmoid(x):
+        return 1. / (1. + np.exp(-x))
+    p = np.squeeze(sigmoid(W[2]))
+    kernel_regularizer = cd.weight_regularizer * np.sum(np.square(W[0])) / (1. - p)
+    dropout_regularizer = (p * np.log(p) + (1. - p) * np.log(1. - p))
+    dropout_regularizer *= cd.dropout_regularizer * 1  # only channels are dropped
+    loss = np.sum(kernel_regularizer + dropout_regularizer)
+    eval_loss = model.evaluate(X)
+    assert_approx_equal(eval_loss, loss)
+
+
+def test_cdropout_wrong_layertype():
+    """To be replaced with a real function test, if implemented.
+    """
+    in_dim = 20
+    init_prop = .1
+    with pytest.raises(ValueError):
+        inputs = Input(shape=(in_dim, in_dim,))
+        ConcreteDropout(Conv1D(1, 3),
+                        in_dim,
+                        prob_init=(init_prop, init_prop))(inputs)
+
+
 if __name__ == '__main__':
     pytest.main([__file__])