def test_fprop(self):
"""
Use an RNN without non-linearity to create the Mersenne numbers
(2 ** n - 1) to check whether fprop works correctly.
"""
rnn = RNN(input_space=SequenceSpace(VectorSpace(dim=1)),
layers=[
Recurrent(dim=1,
layer_name='recurrent',
irange=0.1,
indices=[-1],
nonlinearity=lambda x: x)
])
W, U, b = rnn.layers[0].get_params()
W.set_value([[1]])
U.set_value([[2]])
X_data, X_mask = rnn.get_input_space().make_theano_batch()
y_hat = rnn.fprop((X_data, X_mask))
seq_len = 20
X_data_vals = np.ones((seq_len, seq_len, 1))
X_mask_vals = np.triu(np.ones((seq_len, seq_len)))
f = function([X_data, X_mask], y_hat, allow_input_downcast=True)
np.testing.assert_allclose(2**np.arange(1, seq_len + 1) - 1,
f(X_data_vals, X_mask_vals).flatten())
def test_gradient(self):
"""
Testing to see whether the gradient can be calculated.
"""
rnn = RNN(input_space=SequenceSpace(VectorSpace(dim=1)),
layers=[Recurrent(dim=2, layer_name='recurrent',
irange=0, nonlinearity=lambda x: x),
Linear(dim=1, layer_name='linear', irange=0)])
X_data, X_mask = rnn.get_input_space().make_theano_batch()
y_data, y_mask = rnn.get_output_space().make_theano_batch()
default_cost = Default()
cost = default_cost.expr(rnn, ((X_data, X_mask), (y_data, y_mask)))
tensor.grad(cost, rnn.get_params(), disconnected_inputs='ignore')
def test_cost(self):
"""
Use an RNN to calculate Mersenne number sequences of different
lengths and check whether the costs make sense.
"""
rnn = RNN(input_space=SequenceSpace(VectorSpace(dim=1)),
layers=[
Recurrent(dim=1,
layer_name='recurrent',
irange=0,
nonlinearity=lambda x: x),
Linear(dim=1, layer_name='linear', irange=0)
])
W, U, b = rnn.layers[0].get_params()
W.set_value([[1]])
U.set_value([[2]])
W, b = rnn.layers[1].get_params()
W.set_value([[1]])
X_data, X_mask = rnn.get_input_space().make_theano_batch()
y_data, y_mask = rnn.get_output_space().make_theano_batch()
y_data_hat, y_mask_hat = rnn.fprop((X_data, X_mask))
seq_len = 20
X_data_vals = np.ones((seq_len, seq_len, 1))
X_mask_vals = np.triu(np.ones((seq_len, seq_len)))
y_data_vals = np.tile((2**np.arange(1, seq_len + 1) - 1),
(seq_len, 1)).T[:, :, np.newaxis]
y_mask_vals = np.triu(np.ones((seq_len, seq_len)))
f = function([X_data, X_mask, y_data, y_mask],
rnn.cost((y_data, y_mask), (y_data_hat, y_mask_hat)),
allow_input_downcast=True)
# The cost for two exact sequences should be zero
assert f(X_data_vals, X_mask_vals, y_data_vals, y_mask_vals) == 0
# If the input is different, the cost should be non-zero
assert f(X_data_vals + 1, X_mask_vals, y_data_vals, y_mask_vals) != 0
# And same for the target data; using squared L2 norm, so should be 1
assert f(X_data_vals, X_mask_vals, y_data_vals + 1, y_mask_vals) == 1
# But if the masked data changes, the cost should remain the same
X_data_vals_plus = X_data_vals + (1 - X_mask_vals[:, :, None])
assert f(X_data_vals_plus, X_mask_vals, y_data_vals, y_mask_vals) == 0
y_data_vals_plus = y_data_vals + (1 - y_mask_vals[:, :, None])
assert f(X_data_vals, X_mask_vals, y_data_vals_plus, y_mask_vals) == 0