mxnet 线性模型
mxnet 线性模型
<wiz_code_mirror>
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def data_loader(batch_size, X, y, shuffle=False):
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import mxnet
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import mxnet.ndarray as nd
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from mxnet import gluon
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from mxnet import autograd
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# create data
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def set_data(true_w, true_b, num_examples, *args, **kwargs):
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num_inputs = len(true_w)
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X = nd.random_normal(shape=(num_examples, num_inputs))
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y = 0
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for num in range(num_inputs):
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# print(num)
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y += true_w[num] * X[:, num]
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y += true_b
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y += 0.1 * nd.random_normal(shape=y.shape)
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return X, y
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# create data loader
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def data_loader(batch_size, X, y, shuffle=False):
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data_set = gluon.data.ArrayDataset(X, y)
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data_iter = gluon.data.DataLoader(dataset=data_set, batch_size=batch_size, shuffle=shuffle)
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return data_iter
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# create net
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def set_net(node_num):
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net = gluon.nn.Sequential()
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net.add(gluon.nn.Dense(node_num))
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net.initialize()
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return net
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# create trainer
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def trainer(net, loss_method, learning_rate):
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trainer = gluon.Trainer(
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net.collect_params(), loss_method, {'learning_rate': learning_rate}
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)
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return trainer
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square_loss = gluon.loss.L2Loss()
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# start train
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def start_train(epochs, batch_size, data_iter, net, loss_method, tariner, num_examples):
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for e in range(epochs):
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total_loss = 0
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for data, label in data_iter:
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with autograd.record():
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output = net(data)
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loss = loss_method(output, label)
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loss.backward()
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trainer.step(batch_size)
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total_loss += nd.sum(loss).asscalar()
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print("第 %d次训练, 平均损失: %f" % (e, total_loss / 1000))
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dense = net[0]
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print(dense.weight.data())
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print(dense.bias.data())
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return dense.weight.data(), dense.bias.data()
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true_w = [5, 8, 6]
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true_b = 6
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X, y = set_data(true_w=true_w, true_b=true_b, num_examples=1000)
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data_iter = data_loader(batch_size=10, X=X, y=y, shuffle=True)
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net = set_net(1)
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trainer = trainer(net=net, loss_method='sgd', learning_rate=0.1)
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start_train(epochs=5, batch_size=10, data_iter=data_iter, net=net, loss_method=square_loss, tariner=trainer,
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num_examples=1000)
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