Backprop working

This commit is contained in:
Ritchie 2017-06-30 18:13:59 +02:00
parent 70b4cc7bc9
commit ea28e2ee29
2 changed files with 28 additions and 10 deletions

View File

@ -219,9 +219,6 @@ class Network:
self.n_layers - 1: (dw, delta)
}
# update weights and biases
self.update_w_b(self.n_layers - 1, dw, delta)
# In case of three layer net will iterate over i = 2 and i = 1
# Determine partial derivative and delta for the rest of the layers.
# Each iteration requires the delta from the previous layer, propagating backwards.
@ -244,7 +241,7 @@ class Network:
self.w[index] -= self.learning_rate * np.mean(dw, 1)
self.b[index] -= self.learning_rate * np.mean(np.mean(delta, 1), 0)
def fit(self, x, y_true, loss, epochs, batch_size, learning_rate=1e-3):
def fit(self, x, y_true, loss, epochs, batch_size, learning_rate=2e-2):
"""
:param loss: Loss class (MSE, CrossEntropy etc.)
"""
@ -267,9 +264,13 @@ class Network:
z, a = self.feed_forward(x_[k:l])
self.back_prop(z, a, y_[k:l])
if (i + 1) % 100 == 0:
if (i + 1) % 10 == 0:
print("Loss:", self.loss.loss(y_true, z[self.n_layers]))
def predict(self, x):
_, a = self.feed_forward(x)
return a[self.n_layers]
if __name__ == "__main__":
from sklearn import datasets
#import sklearn.metrics
@ -283,7 +284,21 @@ if __name__ == "__main__":
# one hot encoding
y = np.eye(3)[y]
nn = Network((4, 8, 3), (Relu, Sigmoid))
nn = Network((4, 8, 2, 3), (Relu, Relu, Sigmoid))
nn.fit(x[:2], y[:2], MSE, 1, batch_size=2)
#nn.fit(x, y, MSE, 10000, 16)
#nn.fit(x[:2], y[:2], MSE, 1, batch_size=2)
nn.fit(x, y, MSE, 1000, 16)
y_ = nn.predict(x)
a = np.argmax(y_, 1)
for i in range(a.size):
print(a[i], y[i])
# y_true = []
# y_pred = []
# for i in range(len(y)):
# y_pred.append(np.argmax(y_[3][i]))
# y_true.append(np.argmax(y[i]))
#
# print(sklearn.metrics.classification_report(y_true, y_pred))

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@ -135,7 +135,7 @@ class NeuralNetwork:
# partial derivative with respect to layer 1
delta2 = np.dot(delta3, self.w[2].T) * diff_relu(self.z[2])
print(self.w[2].T)
# dc_db1 = delta2
dc_dw1 = np.dot(self.x.T, delta2)
@ -194,7 +194,10 @@ if __name__ == "__main__":
y = np.eye(3)[y]
nn = NeuralNetwork(4, 8, 3, 2e-2)
nn.fit(x[:2], y[:2], 2, 1)
#nn.fit(x[:2], y[:2], 2, 1)
nn.fit(x, y, 16, 1000)
_, y_ = feed_forward(x, nn.w, nn.b)
print(y_)
# # result
# _, y_ = feed_forward(x, nn.w, nn.b)