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Author | SHA1 | Date |
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Absobel | 1276934c54 |
8
RUN.py
8
RUN.py
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@ -3,13 +3,13 @@
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import mnist_loader
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training_data, validation_data, test_data = mnist_loader.load_data_wrapper()
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print(list(training_data)[0][1])
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#print(list(training_data)[0][1])
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import network
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#net = network.Network([784, 30, 10]) #Testé : 94,56%
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#net.SGD(training_data, 10, 10, 3.0, test_data=None)
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#print("Results : {} / 10000".format(net.evaluate(test_data)))
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net = network.Network([784, 30, 10]) #Testé : 94,56% / 94,87%
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net.SGD(training_data, 30, 10, 3.0, test_data=test_data)
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print("Results : {} / 10000".format(net.evaluate(test_data)))
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# net = network.Network([784, 100, 10]) #Marche mieux apparemment
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# net.SGD(training_data, 30, 10, 3.0, test_data=test_data)
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@ -0,0 +1,106 @@
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import random
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import numpy as np
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class Network(object):
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def __init__(self, sizes):
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"""sizes : [nb neurones input, nb de neurones couche 1, ..., nb de neurones couche n, nb de neurones output]
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biases : seuils générés aléatoirement
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weights : poids générés aléatoirement"""
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self.num_layers = len(sizes)
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self.sizes = sizes
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self.biases = [np.random.randn(y, 1) for y in sizes[1:]]
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self.weights = [np.random.randn(y, x)
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for x, y in zip(sizes[:-1], sizes[1:])]
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def feedforward(self, a):
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for b, w in zip(self.biases, self.weights):
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a = sigmoid(np.dot(w, a)+b)
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return a
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def SGD(self, training_data, epochs, mini_batch_size, eta,
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test_data=None):
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"""epochs : iterations
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eta : taux d'apprentissage
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test_data : s'il y en a pas le programme ne s'arrêtera pas à chaque iterations pour se tester"""
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training_data = list(training_data)
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n = len(training_data)
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if test_data:
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test_data = list(test_data)
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n_test = len(test_data)
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for j in range(epochs):
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random.shuffle(training_data)
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mini_batches = [
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training_data[k:k+mini_batch_size]
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for k in range(0, n, mini_batch_size)]
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for mini_batch in mini_batches:
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self.update_mini_batch(mini_batch, eta)
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if test_data:
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print("Epoch {} : {} / {}".format(j,self.evaluate(test_data),n_test))
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else:
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print("Epoch {} complete".format(j))
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def update_mini_batch(self, mini_batch, eta):
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"""Met à jour les poids et seuils grâce aux gradient descendant"""
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nabla_b = [np.zeros(b.shape) for b in self.biases]
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nabla_w = [np.zeros(w.shape) for w in self.weights]
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for x, y in mini_batch:
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delta_nabla_b, delta_nabla_w = self.backprop(x, y)
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nabla_b = [nb+dnb for nb, dnb in zip(nabla_b, delta_nabla_b)]
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nabla_w = [nw+dnw for nw, dnw in zip(nabla_w, delta_nabla_w)]
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self.weights = [w-(eta/len(mini_batch))*nw
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for w, nw in zip(self.weights, nabla_w)]
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self.biases = [b-(eta/len(mini_batch))*nb
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for b, nb in zip(self.biases, nabla_b)]
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def backprop(self, x, y):
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"""Calcul du gradient descendant"""
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nabla_b = [np.zeros(b.shape) for b in self.biases]
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nabla_w = [np.zeros(w.shape) for w in self.weights]
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# feedforward
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activation = x
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activations = [x] # list to store all the activations, layer by layer
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zs = [] # list to store all the z vectors, layer by layer
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for b, w in zip(self.biases, self.weights):
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z = np.dot(w, activation)+b
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zs.append(z)
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activation = sigmoid(z)
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activations.append(activation)
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# backward pass
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delta = self.cost_derivative(activations[-1], y) * \
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sigmoid_prime(zs[-1])
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nabla_b[-1] = delta
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nabla_w[-1] = np.dot(delta, activations[-2].transpose())
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# Note that the variable l in the loop below is used a little
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# differently to the notation in Chapter 2 of the book. Here,
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# l = 1 means the last layer of neurons, l = 2 is the
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# second-last layer, and so on. It's a renumbering of the
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# scheme in the book, used here to take advantage of the fact
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# that Python can use negative indices in lists.
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for l in range(2, self.num_layers):
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z = zs[-l]
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sp = sigmoid_prime(z)
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delta = np.dot(self.weights[-l+1].transpose(), delta) * sp
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nabla_b[-l] = delta
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nabla_w[-l] = np.dot(delta, activations[-l-1].transpose())
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return (nabla_b, nabla_w)
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def evaluate(self, test_data):
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"""Teste le programme avec le dataset fourni"""
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test_results = [(np.argmax(self.feedforward(x)), y)
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for (x, y) in test_data]
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return sum(int(x == y) for (x, y) in test_results)
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def cost_derivative(self, output_activations, y):
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"""Return the vector of partial derivatives \partial C_x /
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\partial a for the output activations."""
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return (output_activations-y)
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def sigmoid(z):
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return 1.0/(1.0+np.exp(-z))
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def sigmoid_prime(z):
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return sigmoid(z)*(1-sigmoid(z))
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