Softmax Function

Definition

Suppose the number of possible outcomes is $K$, then the softmax function $\mathrm{softmax}(\mathbf{z}):{\mathbb{R}}^K\to (0,1{)}^K$ is defined as $\mathrm{softmax}(\mathbf{z}{)}_i=\frac{\exp (z_i)}{{\sum }_{j=1}^K\exp (z_j)}$