def __init__(self, hidden_layers, input_size=784, num_classes=10):
"""Initializes the neural network.
Args:
hidden_layers: List of ints specifying the sizes of hidden layers. Could
be empty.
input_size: Length of the input array. The network receives the input
image as a flattened 1-d array. Defaults to 784(28*28), the default
image size for MNIST.
num_classes: The number of output classes. Defaults to 10.
"""
hidden_layers = [input_size] + hidden_layers + [num_classes]
self.weights = []
self.biases = []
for i in range(len(hidden_layers) - 1):
# TODO(srbs): This is manually cast to float32 to avoid the cast in
# np.dot since backprop fails for tf.cast op.
self.weights.append(
np.array(np.random.randn(hidden_layers[i + 1],
hidden_layers[i]),
copy=False,
dtype=float32))
self.biases.append(
np.array(np.random.randn(hidden_layers[i + 1]),
copy=False,
dtype=float32))
def test_vmap_out_axes_leaf_types(self):
with self.assertRaisesRegex(
TypeError, r'vmap out_axes must be an int, None, or .*'):
extensions.vmap(lambda x: x,
out_axes=(tf_np.array([1., 2.
]), ))(tf_np.array([1.,
2.]))
def train(self, x, y, learning_rate=0.01):
"""Runs a single training pass.
Args:
x: 2-d array of size batch_size x image_size.
y: 2-d array of size batch_size x num_classes in one-hot notation.
learning_rate: The learning rate.
"""
x = np.array(x, copy=False)
y = np.array(y, copy=False)
def mean_squared_error(x, y):
diff = x - y
return np.sum(diff * diff) / len(x)
wb_tensors = [p.data for p in self.weights + self.biases]
with tf.GradientTape() as g:
g.watch(wb_tensors)
loss = mean_squared_error(self.forward(x), y)
gradients = g.gradient(loss.data, wb_tensors)
new_weights_and_biases = []
for v, dv in zip(self.weights + self.biases, gradients):
new_weights_and_biases.append(v - learning_rate * dv)
total_len = len(new_weights_and_biases)
self.weights = new_weights_and_biases[:total_len // 2]
self.biases = new_weights_and_biases[total_len // 2:]
def testIndexDtypeError(self):
# https://github.com/google/jax/issues/2795
jnp.array(1) # get rid of startup warning
with warnings.catch_warnings(record=True) as w:
warnings.simplefilter("error")
jnp.zeros(5).at[::2].set(1)
self.assertLen(w, 0)
def testBooleanIndexingWithEmptyResult(self):
# based on a TensorFlow Probability test that started failing after #1623
x = jnp.array([-1])
mask = jnp.array([False])
ans = x[mask] # doesn't crash
expected = onp.array([-1])[onp.array([False])]
self.assertAllClose(ans, expected, check_dtypes=False)
def test_vmap_mismatched_axis_sizes_error_message_issue_705(self):
# https://github.com/google/jax/issues/705
with self.assertRaisesRegex(
ValueError, 'vmap must have at least one non-None value in in_axes'):
# If the output is mapped, there must be a non-None in_axes
extensions.vmap(lambda x: x, in_axes=None)(tf_np.array([1., 2.]))
# Error is: TypeError: only integer scalar arrays can be converted to a
# scalar index
with self.assertRaisesRegex(
ValueError, 'vmap out_axes specification must be a tree prefix of the '
'corresponding value.*'):
extensions.vmap(
lambda x: x, in_axes=0, out_axes=(2, 3))(
tf_np.array([1., 2.]))
def sugar_fn(op, indexer, x, y):
x = jnp.array(x)
return {
UpdateOps.UPDATE: x.at[indexer].set,
UpdateOps.ADD: x.at[indexer].add,
UpdateOps.MUL: x.at[indexer].mul,
UpdateOps.MIN: x.at[indexer].min,
UpdateOps.MAX: x.at[indexer].max,
}[op](y)
def evaluate(self, x, y):
"""Returns the number of correct predictions.
Args:
x: 2-d array of size batch_size x image_size.
y: 2-d array of size batch_size x num_classes.
Returns:
A scalar, the number of correct predictions.
"""
y_actual = np.argmax(y, axis=1)
y_predicted = np.argmax(self.forward(x), axis=1)
return int(
np.sum(np.array(y_actual == y_predicted, copy=False, dtype=int32)))
def f(x):
if isinstance(x, (tf.Tensor, tf.IndexedSlices)):
return tf_np.array(x, copy=False)
else:
return x
