1 files changed, 54 insertions, 0 deletions
diff --git a/src/activationFunctions.js b/src/activationFunctions.js
new file mode 100644
index 0000000..6ccc046
--- /dev/null
+++ b/src/activationFunctions.js
@@ -0,0 +1,54 @@
+console.log('Hello from activationFunctions.js');
+
+let sigmoidExpression = '1 / (1 + exp(-x))';
+let dSigmoidExpression = math.derivative(sigmoidExpression, 'x');
+
+sigmoidExpression = math.compile(sigmoidExpression);
+dSigmoidExpression = dSigmoidExpression.toString();
+dSigmoidExpression = math.compile(dSigmoidExpression);
+
+const sigmoid = function(xValue) {
+	return sigmoidExpression.evaluate({x: xValue});
+};
+
+const dSigmoid_dx = function(xValue) {
+	return dSigmoidExpression.evaluate({x: xValue});
+};
+
+const relu = function(x) {
+	return x * (x > 0);
+};
+
+const dRelu_dx = function(x) {
+	return Number(x > 0);
+};
+
+const identity = function(x) {
+	return x;
+};
+
+const dIdentity_dx = function(x) {
+	return 1;
+};
+
+const matrixMethod = function(elementMethod) {
+	const method = function(matrix) {
+		return math.map(matrix, (element) => elementMethod(element));
+	};
+	return method;
+};
+
+activationFunctionList = {
+	'relu': {
+		gx: matrixMethod(relu),
+		dg_dx: matrixMethod(dRelu_dx)
+	},
+	'sigmoid': {
+		gx: matrixMethod(sigmoid),
+		dg_dx: matrixMethod(dSigmoid_dx)
+	},
+	'identity': {
+		gx: matrixMethod(identity),
+		dg_dx: matrixMethod(dIdentity_dx)
+	}
+};
+\ No newline at end of file