Added Softmax to Maths folder (#516)

Maths/Softmax.js

@@ -0,0 +1,13 @@
+// Wikipedia: https://en.wikipedia.org/wiki/Softmax_function
+
+const Softmax = (inputs) => {
+  const eulerExpOfAllInputs = inputs.map(input => Math.exp(input))
+  const sumOfEulerExpOfAllInputs = eulerExpOfAllInputs.reduce((a, b) => a + b)
+
+  return inputs.map((input) => {
+    const eulerExpInputs = Math.exp(input)
+    return eulerExpInputs / sumOfEulerExpOfAllInputs
+  })
+}
+
+export { Softmax }