Created
October 19, 2017 21:25
-
-
Save michaelguia/6a2892c47dacc625f190650d720f74b8 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
def to_categorical(y, num_classes=None): | |
"""Converts a class vector (integers) to binary class matrix. | |
E.g. for use with categorical_crossentropy. | |
# Arguments | |
y: class vector to be converted into a matrix | |
(integers from 0 to num_classes). | |
num_classes: total number of classes. | |
# Returns | |
A binary matrix representation of the input. | |
""" | |
y = np.array(y, dtype='int').ravel() | |
if not num_classes: | |
num_classes = np.max(y) + 1 | |
n = y.shape[0] | |
categorical = np.zeros((n, num_classes)) | |
categorical[np.arange(n), y] = 1 | |
return categorical | |
def normalize(x, axis=-1, order=2): | |
"""Normalizes a Numpy array. | |
# Arguments | |
x: Numpy array to normalize. | |
axis: axis along which to normalize. | |
order: Normalization order (e.g. 2 for L2 norm). | |
# Returns | |
A normalized copy of the array. | |
""" | |
l2 = np.atleast_1d(np.linalg.norm(x, order, axis)) | |
l2[l2 == 0] = 1 | |
return x / np.expand_dims(l2, axis) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment