chainer.functions.expand_dims¶
-
chainer.functions.
expand_dims
(x, axis)[source]¶ Expands dimensions of an input variable without copy.
- Parameters
x (
Variable
or N-dimensional array) – Input variable.axis (int) – Position where new axis is to be inserted. The
axis
parameter is acceptable when \(-ndim - 1 \leq axis \leq ndim\). (ndim
is the dimension of input variables). When \(axis < 0\), the result is the same with \(ndim + 1 - |axis|\).
- Returns
Variable that holds an expanded input. The
ndim
of output is one greater than that ofx
.- Return type
Example
>>> x = np.array([1, 2, 3]) >>> x.shape (3,) >>> y = F.expand_dims(x, axis=0) >>> y.shape (1, 3) >>> y.array array([[1, 2, 3]]) >>> y = F.expand_dims(x, axis=1) >>> y.shape (3, 1) >>> y.array array([[1], [2], [3]]) >>> y = F.expand_dims(x, axis=-2) >>> y.shape (1, 3) >>> y.array array([[1, 2, 3]])