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boston.py
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boston.py
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from keras.datasets import boston_housing
(train_data, train_targets), (test_data, test_targets) = boston_housing.load_data()
mean = train_data.mean(axis=0)
train_data -= mean
std = train_data.std(axis=0)
train_data /= std
test_data -= mean
test_data /= std
from keras import models
from keras import layers
def build_model():
input = layers.Input(shape=(train_data.shape[1],))
output = layers.Dense(64, activation='relu')(input)
output = layers.Dense(64, activation='relu')(output)
output = layers.Dense(1)(output)
model = models.Model(input=input, output=output)
model.compile(optimizer='rmsprop', loss='mse', metrics=['mae'])
return model
import numpy as np
k = 4
num_val_samples = len(train_data) // k
num_epochs = 500
all_mae_histories = []
for i in range(k):
print('processing fold #', i)
val_data = train_data[i * num_val_samples: (i + 1) * num_val_samples]
val_targets = train_targets[i * num_val_samples: (i + 1) * num_val_samples]
partial_train_data = np.concatenate([train_data[:i * num_val_samples], train_data[(i + 1) * num_val_samples:]],
axis=0)
partial_train_targets = np.concatenate(
[train_targets[:i * num_val_samples], train_targets[(i + 1) * num_val_samples:]], axis=0)
model = build_model()
history = model.fit(partial_train_data, partial_train_targets, validation_data=(val_data, val_targets),
epochs=num_epochs, batch_size=1, verbose=0)
mae_history = history.history['val_mean_absolute_error']
all_mae_histories.append(mae_history)
average_mae_history = [np.mean([x[i] for x in all_mae_histories]) for i in range(num_epochs)]
import matplotlib.pyplot as plt
plt.plot(range(1, len(average_mae_history) + 1), average_mae_history)
plt.xlabel('Epochs')
plt.ylabel('Validation MAE')
plt.show()
def smooth_curve(points, factor=0.9):
smoothed_points = []
for point in points:
if smoothed_points:
previous = smoothed_points[-1]
smoothed_points.append(previous * factor + point * (1 - factor))
else:
smoothed_points.append(point)
return smoothed_points
smooth_mae_history = smooth_curve(average_mae_history[10:])
plt.plot(range(1, len(smooth_mae_history) + 1), smooth_mae_history)
plt.xlabel('Epochs')
plt.ylabel('Validation MAE')
plt.show()
model = build_model()
model.fit(train_data, train_targets, epochs=80, batch_size=16, verbose=0)
test_mse_score, test_mae_score = model.evaluate(test_data, test_targets)
print(test_mse_score)
import matplotlib.pyplot as plt
result = model.predict(test_data)
x = range(1, len(test_targets) + 1)
plt.scatter(x, test_targets, c='b')
plt.scatter(x, result, c='r')
plt.show()