【发布时间】:2017-07-27 07:12:02
【问题描述】:
定义我的神经网络并训练我的模型后:
net = tflearn.input_data(shape=[None, 1, 1])
tnorm = tflearn.initializations.uniform(minval=-1.0, maxval=1.0)
net = tflearn.lstm(net, timesteps, dropout=0.8)
net = tflearn.fully_connected(net, 1, activation='linear', weights_init=tnorm)
net = tflearn.regression(net, optimizer='adam', learning_rate=0.001,
loss='mean_square', metric='R2')
# Define model
model = tflearn.DNN(net, clip_gradients=0.)
model.fit(X, y, n_epoch=nb_epoch, batch_size=batch_size, shuffle=False, show_metric=True)
score = model.evaluate(X, y, batch_size=128)
model.save('ModeSpot.tflearn')
我现在遇到了一个问题,我发现的大多数时间序列预测教程都使用测试集进行预测(他们将测试集提供给 .predict())。问题是实际上我们不知道这一点,因为这是我们想要预测的。
现在我正在使用它:
def forecast_lstm(model, X):
X = X.reshape(len(X), 1, 1)
yhat = model.predict(X)
return yhat[0, 0]
# split data into train and test-sets
train, test = supervised_values[0:-10000], supervised_values[-10000:]
# transform the scale of the data
scaler, train_scaled, test_scaled = scale(train, test)
# Build neural network
net = tflearn.input_data(shape=[None, 1, 1])
tnorm = tflearn.initializations.uniform(minval=-1.0, maxval=1.0)
net = tflearn.lstm(net, 1, dropout=0.3)
net = tflearn.fully_connected(net, 1, activation='linear', weights_init=tnorm)
net = tflearn.regression(net, optimizer='adam', learning_rate=0.001,
loss='mean_square', metric='R2')
lstm_model = tflearn.DNN(net, clip_gradients=0.)
lstm_model.load('ModeSpot.tflearn')
# forecast the entire training dataset to build up state for forecasting
train_reshaped = train_scaled[:, 0].reshape(len(train_scaled), 1, 1)
lstm_model.predict(train_reshaped)
# walk-forward validation on the test data
predictions = list()
error_scores = list()
for i in range(len(test_scaled)):
# make one-step forecast
X, y = test_scaled[i, 0:-1], test_scaled[i, -1]
yhat = forecast_lstm(lstm_model, X)
# invert scaling
yhat2 = invert_scale(scaler, X, yhat)
# # invert differencing
yhat3 = inverse_difference(raw_values, yhat2, len(test_scaled) + 1 - i)
# store forecast
predictions.append(yhat3)
但它只适用于我的测试集。如何预测下一个 x 值? 我想我已经在某处看到要预测 T 的值,我必须使用 T-1 的值进行预测(然后 T 表示 T+1 ,直到我达到我想要的预测数量)。这是一个好方法吗?
我已经尝试过这样做:
def forecast_lstm2(model, X):
X = X.reshape(-1, 1, 1)
yhat = model.predict(X)
return yhat[0, 0]
test = list()
X, y = train_scaled[0, 0:-1], train_scaled[0, -1]
test.append(X)
for i in range(len(test_scaled)):
# make one-step forecast
yhat = forecast_lstm2(lstm_model, test[i])
test.append(yhat)
# invert scaling
yhat2 = invert_scale(scaler, test[i+1], yhat)
# # invert differencing
yhat3 = inverse_difference(raw_values, yhat2, len(test) + 1 - i)
# store forecast
predictions.append(yhat3)
但它没有达到预期的效果(经过一些预测,它总是给出相同的结果)。
感谢您的关注和时间。
【问题讨论】:
标签: python python-2.7 machine-learning lstm tflearn