# chainer.functions.sign¶

chainer.functions.sign(x)[source]

Elementwise sign function.

For a given input $$x$$, this function returns $$sgn(x)$$ defined as

$\begin{split}sgn(x) = \left \{ \begin{array}{cc} -1 & {\rm if~x < 0} \\ 0 & {\rm if~x = 0} \\ 1 & {\rm if~x > 0} \\ \end{array} \right.\end{split}$

Note

The gradient of this function is None everywhere and therefore unchains the computational graph.

Parameters: x (Variable or N-dimensional array) – Input variable for which the sign is computed. Output variable. Variable