In [1]:
from __future__ import print_function
from keras.models import Sequential
from keras.layers import Dense, Activation
from keras.layers import SimpleRNN
from keras.optimizers import RMSprop
from keras.utils.data_utils import get_file
import matplotlib.pyplot as plt
import numpy as np
import random
import sys
path = 'data/input.txt'
text = open(path).read()
print('text length:', len(text))
chars = sorted(list(set(text)))
print('total chars:', len(chars))
char_indices = dict((c, i) for i, c in enumerate(chars))
indices_char = dict((i, c) for i, c in enumerate(chars))
In [41]:
maxlen = 30
sentences = []
next_chars = []
for i in range(0, 100):
j = random.randint(0, len(text) - maxlen - 1)
sentences.append(text[j: j + maxlen])
next_chars.append(text[j + maxlen + 1])
print('nb sequences:', len(sentences))
print('Vectorization...')
X = np.zeros((len(sentences), maxlen, len(chars)), dtype=np.bool)
y = np.zeros((len(sentences), len(chars)), dtype=np.bool)
for i, sentence in enumerate(sentences):
for t, char in enumerate(sentence):
X[i, t, char_indices[char]] = 1
y[i, char_indices[char]] = 1
val_per = 0.2
X_train = X[int(X.shape[0] * val_per):-1, :, :]
y_train = y[int(X.shape[0] * val_per):-1, :]
X_val = X[1:int(X.shape[0] * val_per), :, :]
y_val = y[1:int(X.shape[0] * val_per), :]
In [40]:
y_train.shape
Out[40]:
In [4]:
model = Sequential()
model.add(SimpleRNN(100, input_shape=(maxlen, len(chars))))
model.add(Dense(len(chars)))
model.add(Activation('softmax'))
optimizer = RMSprop(lr=0.01)
model.compile(loss='categorical_crossentropy', optimizer=optimizer)
In [5]:
def sample(preds, temperature=1.0):
preds = np.asarray(preds).astype('float64')
preds = np.log(preds) / temperature
exp_preds = np.exp(preds)
preds = exp_preds / np.sum(exp_preds)
probas = np.random.multinomial(1, preds, 1)
return np.argmax(probas)
In [42]:
history = model.fit(X_train, y_train, batch_size=1, nb_epoch=5, validation_data=(X_val, y_val))
plt.plot(history.history['loss'])
plt.plot(history.history['val_loss'])
plt.title('model loss')
plt.ylabel('loss')
plt.xlabel('epoch')
plt.legend(['train', 'test'], loc='upper left')
plt.show()
start_index = random.randint(0, len(text) - maxlen - 1)
for diversity in [1.0]:
print()
print('----- diversity:', diversity)
generated = ''
sentence = text[start_index: start_index + maxlen]
generated += sentence
print('----- Generating with seed: "' + sentence + '"')
sys.stdout.write(generated)
for i in range(20):
x = np.zeros((1, maxlen, len(chars)))
for t, char in enumerate(sentence):
x[0, t, char_indices[char]] = 1.
preds = model.predict(x, verbose=0)[0]
next_index = sample(preds, diversity)
next_char = indices_char[next_index]
generated += next_char
sentence = sentence[1:] + next_char
sys.stdout.write(next_char)
sys.stdout.flush()
print()
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