Weights in Multi Layer Neural Network

Question

I am developing a multi Layered neural network for my study. But now I am in a fix where, a user should define the number of hidden layers he wants and the number of neurons in each layer. My inputs are of the matrix (x,8) and my actual output is of the matrix (x,2) where x is the number of rows in my sample data.

I usually define my weights as

Weights1 = 2 * np.random.random((Hidden_layer_len,X[0].shape[0])) - 1
Weights2 = 2 * np.random.random((T[0].shape[0],Hidden_layer_len)) - 1
W = [Weights1, Weights2]

where X is the input, T is the output from the sample datasheet and Hidden_layer_len is the length of the hidden layer, assuming there is one hidden layer between my input and output.

Now, my requirement is that, a user can provide the number of hidden layer he wants between the input and output and the user can also define the number of neurons (hidden_layer_len) of each layer.

assuming that there are n layers, how do i create my weights for the n layers and the number of neurons in each layer?

A. Dev A. Dev · Accepted Answer · 2015-10-14T14:29:41

I would recommend using the Pybrain Module to easily create neural networks. Their documentation can be found here:

http://pybrain.org/docs/tutorial/netmodcon.html

The weight will be initialized randomly in the network creation as you are trying to do, and the amount of hidden neurons and hidden layers can be changed. A simple 2 hidden layer neural network with 10 hidden neurons per layer example:

from pybrain.structure import FeedForwardNetwork
n = FeedForwardNetwork()

from pybrain.structure import LinearLayer, SigmoidLayer
inLayer = LinearLayer(8)
hiddenLayer = SigmoidLayer(10)
hiddenLayer2 = SigmoidLayer(10)
outLayer = LinearLayer(2)

n.addInputModule(inLayer)
n.addModule(hiddenLayer)
n.addModule(hiddenLayer2)
n.addOutputModule(outLayer)

from pybrain.structure import FullConnection
in_to_hidden = FullConnection(inLayer, hiddenLayer1)
hidden_to_hidden = FullConnection(hiddenLayer1, hiddenLayer2)
hidden_to_out = FullConnection(hiddenLayer2, outLayer)

n.addConnection(in_to_hidden)
n.addConnection(hidden_to_hidden)
n.addConnection(hidden_to_out)

n.sortModules()

Weights in Multi Layer Neural Network

2 Answers