EmilianoMusso.NeuralNetwork 1.5.0

Please check the following documentation for a quick overview on the library, and how to use it

Using Namespace

using emNeuralNet;

Classes

• NeuralNetwork
• Layer
• Neuron
• Dendrite
• ActivationFunctions
• NeuralData
• RandomGenerator

NeuralNetwork class

Probably the only class you will directly refer into your projects, being other classes used by it. Initialize a NeuralNetwork is done by:

NeuralNetwork nw = new NeuralNetwork(1.25, new int[]{ 2, 2, 1 }, ActivationFunctions.Activation.SIGMOID, "TestNet");

The first parameter of constructor is the learning rate, the second one (an array of int) define how many layers are in our network (in the example, 3 layers) and their number indicates respectively how many neurons to create for that layer (in the example: layer 1 has 2 neurons, layer 2 has 2 neurons, and layer 3 has a single neuron). ActivationFunction can be SIGMOID, TANH, STEP. The last parameter is the network name (optional).

Networks can be trained with Train() method: NeuralData outx = new NeuralData(0); nw.Train(new NeuralData(0, 0), outx, 5);

In the above example, we'll use the NeuralData class for input feeding and output retrieving. The first line means outx will have a single value (in this case, is an expected result) of zero. While training, we use a new NeuralData with two input values of zero and zero. That means we'll execute 5 iterations with two inputs of zero value, and we expect our network to return a single value of zero.

NeuralData has also a static method to quickly convert an integer to binary representation, with leading zeros. Its useful when you want to translate a numerical value to a set of binary values. For example, lets suppose to have five input neurons, and we want to initialize the input neurons with value 10:

var ndata = new NeuralData( NeuralData.ConvertToBinary(10, 5) );

In the above line, 10 is the value we desire to translate to binary, and 5 is the number of neurons our input value must be splitted on. After that instruction, nData will be an array of double, containing the values 0 1 0 1 0, being more apt to be passed at our input layer.

A neural network can be executed with Run() method. For example:

NeuralData outp = nw.Run(new NeuralData(0, 0));

Our network will run with two input values (zero and zero), and returns its result into the outp variable.

NeuralNetwork class has at the moment two methods to give a representation of itself:

• ToString(), which returns text informations about the network itself (number of layers, neurons, biases, delta, value, and so on)
• SaveImage(), which will save a 1600x1200 jpg file graphically representing the network in the given location

Other usefule methods are Save() and Load(): those methods will come in handy to save to a file a trained network status, and being able to restore it later

RandomGenerator class

The class is mainly used in neuron bias and dendrite weight random initialization. It achieves a better randomness ratio than the standard .NET Random class, because it uses RNGCryptoServiceProvider class. If you wish to use it externally to the purposes of the neural network context, a typical calling for the class would be:

RandomGenerator gen = new RandomGenerator(); double rand_value = gen.RandomValue;

ActivationFunctions class

ActivationFunction is internally used to execute a different function in setting the neurons value during training. Current release allows three activation functions, being them:

• Sigmoid
• TanH
• Step

NeuralNetwork class will call the Activate() method during training, passing as parameters the chosen activation function, and the input data.

The library code relies - for the part concerning the core of neural network - on what was presented in the article Basis of Neural Networks in C#, which i wrote in December 2016. Here you could read a more in-depth analysis about neural networks in general.