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# %%
from __future__ import print_function
import numpy as np
from six.moves import range
class CharacterTable(object):
def __init__(self, chars):
"""Initialize character table.
# Arguments
chars: Characters that can appear in the input.
"""
self.chars = sorted(set(chars))
self.char_indices = dict((c, i) for i, c in enumerate(self.chars))
self.indices_char = dict((i, c) for i, c in enumerate(self.chars))
def encode(self, C, num_rows):
"""One hot encode given string C.
# Arguments
num_rows: Number of rows in the returned one hot encoding. This is
used to keep the # of rows for each data the same.
"""
x = np.zeros((num_rows, len(self.chars)))
for i, c in enumerate(C):
x[i, self.char_indices[c]] = 1
return x
def decode(self, x, calc_argmax=True):
if calc_argmax:
x = x.argmax(axis=-1)
return ''.join(self.indices_char[x] for x in x)
class colors:
ok = '\033[92m'
fail = '\033[91m'
close = '\033[0m'
# --
# Parameters for the model and dataset.
TRAINING_SIZE = 50000
DIGITS = 3
REVERSE = True
# Maximum length of input is 'int + int' (e.g., '345+678'). Maximum length of int is DIGITS.
MAXLEN = DIGITS + 1 + DIGITS
# All the numbers, plus sign and space for padding.
chars = '0123456789+ '
ctable = CharacterTable(chars)
questions = []
expected = []
seen = set()
print('Generating data...')
while len(questions) < TRAINING_SIZE:
f = lambda: int(''.join(np.random.choice(list('0123456789'))
for _ in range(np.random.randint(1, DIGITS + 1))))
a, b = f(), f()
# Skip any addition questions we've already seen
# Also skip any such that x+Y == Y+x (hence the sorting).
key = tuple(sorted((a, b)))
if key in seen:
continue
seen.add(key)
# Pad the data with spaces such that it is always MAXLEN.
q = '{}+{}'.format(a, b)
query = q + ' ' * (MAXLEN - len(q))
ans = str(a + b)
# Answers can be of maximum size DIGITS + 1.
ans += ' ' * (DIGITS + 1 - len(ans))
if REVERSE:
# Reverse the query, e.g., '12+345 ' becomes ' 543+21'. (Note the
# space used for padding.)
query = query[::-1]
questions.append(query)
expected.append(ans)
print('Total addition questions:', len(questions))
print('Vectorization...')
x = np.zeros((len(questions), MAXLEN, len(chars)), dtype=np.bool)
y = np.zeros((len(questions), DIGITS + 1, len(chars)), dtype=np.bool)
for i, sentence in enumerate(questions):
x[i] = ctable.encode(sentence, MAXLEN)
for i, sentence in enumerate(expected):
y[i] = ctable.encode(sentence, DIGITS + 1)
# Shuffle (x, y) in unison as the later parts of x will almost all be larger digits.
indices = np.arange(len(y))
np.random.shuffle(indices)
x = x[indices]
y = y[indices]
# Explicitly set apart 10% for validation data that we never train over.
split_at = len(x) - len(x) // 10
(x_train, x_val) = x[:split_at], x[split_at:]
(y_train, y_val) = y[:split_at], y[split_at:]
print('Training Data:')
print(x_train.shape)
print(y_train.shape)
print('Validation Data:')
print(x_val.shape)
print(y_val.shape)
# --
# %%
from keras.models import Sequential
from keras.layers import LSTM, RepeatVector, Dense, Activation, TimeDistributed
from seq2seq.models import SimpleSeq2Seq, AttentionSeq2Seq, Seq2Seq
BATCH_SIZE = 64
print('Build model...')
model = Sequential()
# model.add(AttentionSeq2Seq(32, 4, input_dim=len(chars), input_length=MAXLEN, hidden_dim=64))
model.add(Seq2Seq(32, 4, input_dim=len(chars), input_length=MAXLEN, hidden_dim=64))
# model.add(SimpleSeq2Seq(32, 4, input_dim=len(chars), input_length=MAXLEN, hidden_dim=64))
model.add(Dense(12))
model.add(Activation('softmax'))
model.compile(loss='categorical_crossentropy',
optimizer='adam', metrics=['accuracy'])
model.summary()
# %%
history = model.fit(x_train, y_train,
batch_size=BATCH_SIZE,
epochs=10,
validation_data=(x_val, y_val))
# %%
import matplotlib.pyplot as plt
# summarize history for accuracy
plt.plot(history.history['acc'])
plt.plot(history.history['val_acc'])
plt.title('model accuracy')
plt.ylabel('accuracy')
plt.xlabel('epoch')
plt.legend(['train', 'test'], loc='upper left')
plt.show()
# %%
# Select 10 samples from the validation set at random so we can visualize errors.
for i in range(10):
ind = np.random.randint(0, len(x_val))
rowx, rowy = x_val[np.array([ind])], y_val[np.array([ind])]
preds = model.predict_classes(rowx)
q = ctable.decode(rowx[0])
correct = ctable.decode(rowy[0])
guess = ctable.decode(preds[0], calc_argmax=False)
print('%5d' % ind, end=': ')
print('Q', q[::-1] if REVERSE else q, end=' ')
print('T', correct, end=' ')
if correct == guess:
print(colors.ok + '' + colors.close, end=' ')
else:
print(colors.fail + '' + colors.close, end=' ')
print(guess)