DL之DNN：自定義2層神經網絡TwoLayerNet模型(封裝為層級結構)利用MNIST數據集進行訓練、GC對比

導讀
? ? ? ? ? 神經網絡算法封裝為層級結構的作用。在神經網絡算法中，通過將神經網絡的組成元素實現為層，可以高效地計算梯度（反向傳播法）。通過比較數值微分和誤差反向傳播法的結果，可以確認誤差反向傳播法的實現是否正確（梯度確認）。

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目錄

輸出結果

設計思路

核心代碼

代碼實現過程錯誤記錄

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輸出結果

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設計思路

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核心代碼

class TwoLayerNet:def __init__(self, input_size, hidden_size, output_size, weight_init_std = 0.01):self.params = {}self.params['W1'] = weight_init_std * np.random.randn(input_size, hidden_size)self.params['b1'] = np.zeros(hidden_size)self.params['W2'] = weight_init_std * np.random.randn(hidden_size, output_size) self.params['b2'] = np.zeros(output_size)self.layers = OrderedDict()self.layers['Affine1'] = Affine(self.params['W1'], self.params['b1'])self.layers['Relu1'] = Relu()self.layers['Affine2'] = Affine(self.params['W2'], self.params['b2'])self.lastLayer = SoftmaxWithLoss()def predict(self, x):for layer in self.layers.values():x = layer.forward(x)return x# x:輸入數據, t:監督數據def loss(self, x, t):y = self.predict(x)return self.lastLayer.forward(y, t)def accuracy(self, x, t):y = self.predict(x)y = np.argmax(y, axis=1)if t.ndim != 1 : t = np.argmax(t, axis=1)accuracy = np.sum(y == t) / float(x.shape[0])return accuracydef gradient(self, x, t):self.loss(x, t)dout = 1dout = self.lastLayer.backward(dout)layers = list(self.layers.values())layers.reverse()for layer in layers:dout = layer.backward(dout)grads = {}grads['W1'], grads['b1'] = self.layers['Affine1'].dW, self.layers['Affine1'].dbgrads['W2'], grads['b2'] = self.layers['Affine2'].dW, self.layers['Affine2'].dbreturn gradsnetwork_batch = TwoLayerNet(input_size=784, hidden_size=50, output_size=10)grad_numerical = network_batch.numerical_gradient_api(x_batch, t_batch) grad_backprop = network_batch.gradient(x_batch, t_batch)

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代碼實現過程錯誤記錄

出現錯誤，待解決!!!

Traceback (most recent call last):
? File "F:\File_Python\Python_daydayup\190316.py", line 281, in <module>
? ? grad = network.gradient(x_batch, t_batch) ? ? ? ? ? ??
? File "F:\File_Python\Python_daydayup\190316.py", line 222, in gradient
? ? self.loss(x, t)
? File "F:\File_Python\Python_daydayup\190316.py", line 193, in loss
? ? return self.lastLayer.forward(y, t) # ? ? ? ? ☆★☆★☆★☆★☆★☆★☆★☆★☆★☆★☆★☆★☆★☆ ? ------部分更改
? File "F:\File_Python\Python_daydayup\190316.py", line 132, in forward
? ? self.loss = cross_entropy_error(self.y, self.t)
? File "F:\File_Python\Python_daydayup\190316.py", line 39, in cross_entropy_error
? ? return -np.sum(np.log(y[np.arange(batch_size), t.astype('int64')] + 1e-7)) / batch_size ? ? ? ? ?#t.astype('int64')
IndexError: shape mismatch: indexing arrays could not be broadcast together with shapes (100,) (100,10)?

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DL之DNN：自定義2層神經網絡TwoLayerNet模型(層級結構更高效)算法對MNIST數據集進行訓練、預測

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