new doc and optical backprop

include/NeuralNetwork/Learning/OpticalBackPropagation.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include "./BackPropagation.h"
+
+namespace NeuralNetwork {
+namespace Learning {
+
+	/** @class OpticalBackPropagation
+	 * @brief 
+	 */
+	class OpticalBackPropagation : public BackPropagation {
+
+		public:
+			OpticalBackPropagation(): BackPropagation() {
+
+			}
+			virtual ~OpticalBackPropagation() {
+			}
+
+		protected:
+			inline virtual float correction(const float & expected, const float &computed) const override {
+				register float tmp=(expected-computed);
+				register float ret=1+exp(tmp*tmp);
+				return tmp < 0? -ret:ret;
+			};
+	};
+}
+}