Artificial Intelligence is getting embedded in our lives on a regular basis in form of various speech recognition software, digital assistants like Cortana or, the famous deep dreaming robot of Google – that turns pictures and video into horror movies. All this intelligence comes from a software called neural networks. Recently, a programmer shared a neural network tutorial from scratch starting from an 11 lines of neural network python code.
Backpropagation is a common training method in neural networks that needs a known and desired output for calculating the losses/gradient. The programmer teaches a neural network implementation describing the inner workings of backpropagation via a very simple toy example.
This backpropagation is shown via a small python implementation. Take a look at this neural network in 11 lines of python:
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X = np.array([ [0,0,1],[0,1,1],[1,0,1],[1,1,1] ]) y = np.array([[0,1,1,0]]).T syn0 = 2*np.random.random((3,4)) - 1 syn1 = 2*np.random.random((4,1)) - 1 for j in xrange(60000): l1 = 1/(1+np.exp(-(np.dot(X,syn0)))) l2 = 1/(1+np.exp(-(np.dot(l1,syn1)))) l2_delta = (y - l2)*(l2*(1-l2)) l1_delta = l2_delta.dot(syn1.T) * (l1 * (1-l1)) syn1 += l1.T.dot(l2_delta) syn0 += X.T.dot(l1_delta)
This neural network attempts to use the input for predicting the output. Here programmer tries to predict the output column of the three input columns. Well, this was all I had to tell you about the neural network in 11 lines of python. This problem of simple backpropagation could be used to make a more advanced 2 layer neural network.
Visit this link to read further 2 and 3 layer neural network problems in python.
Try this 11 line python neural network and get more help on python in AI here.