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exercises-in-programming-style/37-dnn/normalize-chars.py
Crista Lopes 5a2b5975c7 Some renaming
2019-12-26 10:40:03 -08:00

143 lines
4.3 KiB
Python

from keras.models import Model
from keras import layers, metrics
from keras.layers import Input, Dense
from keras.utils import plot_model
import numpy as np
import sys, os, string, random
characters = sorted(string.printable)
char_indices = dict((c, i) for i, c in enumerate(characters))
indices_char = dict((i, c) for i, c in enumerate(characters))
INPUT_VOCAB_SIZE = len(characters)
LINE_SIZE = 100
BATCH_SIZE = 200
def encode_one_hot(s):
"""One-hot encode all characters of the given string.
"""
all = []
for c in s:
x = np.zeros((INPUT_VOCAB_SIZE))
index = char_indices[c]
x[index] = 1
all.append(x)
return all
def encode_one_hot2(s):
"""One-hot encode all characters of the given string.
"""
x = np.zeros((LINE_SIZE, INPUT_VOCAB_SIZE))
for n, c in enumerate(s):
index = char_indices[c]
x[n, index] = 1
return x
def decode_one_hot(x):
"""Return a string from a one-hot-encoded matrix
"""
s = []
for onehot in x:
one_index = np.argmax(onehot)
c = indices_char[one_index]
s.append(c)
return ''.join(s)
def build_model():
print('Build model...')
# Normalize every character in the input, using a shared dense model
n_layer = Dense(INPUT_VOCAB_SIZE, activation = "softmax")
raw_inputs = []
normalized_outputs = []
for _ in range(0, LINE_SIZE):
input_char = Input(shape=(INPUT_VOCAB_SIZE, ))
filtered_char = n_layer(input_char)
raw_inputs.append(input_char)
normalized_outputs.append(filtered_char)
merged_output = layers.concatenate(normalized_outputs, axis=-1)
reshape = layers.Reshape((LINE_SIZE, INPUT_VOCAB_SIZE, ))
reshaped_output = reshape(merged_output)
model = Model(inputs=raw_inputs, outputs=reshaped_output)
model.compile(loss='categorical_crossentropy',
optimizer='adam',
metrics=['accuracy'])
return model
def input_generator(nsamples):
def generate_line():
input_data = [random.choice(characters) for _ in range(random.randint(1, LINE_SIZE))]
expected = [c.lower() if c in string.ascii_letters else ' ' for c in input_data]
return input_data, expected
while True:
data_in = [[] for _ in range(LINE_SIZE)]
data_out = np.zeros((nsamples, LINE_SIZE, INPUT_VOCAB_SIZE))
for n in range(nsamples):
input_data, expected = generate_line()
input_data = encode_one_hot(input_data)
for i, c in enumerate(input_data):
data_in[i].append(c)
for j in range(len(input_data), LINE_SIZE):
data_in[j].append(np.zeros((INPUT_VOCAB_SIZE)))
data_out[n] = encode_one_hot2(expected)
inputs = [np.array(e) for e in data_in]
yield inputs, data_out
model = build_model()
#model.summary()
plot_model(model, to_file='normalization.png', show_shapes=True)
# Train the model each generation and show predictions against the validation
# dataset.
val_gen2 = input_generator(1)
for iteration in range(1, 12):
print()
print('-' * 50)
print('Iteration', iteration)
input_gen = input_generator(BATCH_SIZE)
val_gen = input_generator(BATCH_SIZE)
model.fit_generator(input_gen,
epochs = 1,
steps_per_epoch = 20,
validation_data = val_gen,
validation_steps = 10, workers=1)
# Select samples from the a set at random so we can visualize errors.
batch_x, batch_y = next(val_gen2)
for i in range(len(batch_y)):
preds = model.predict(batch_x)
expected = batch_y[i]
prediction = preds[i]
correct = decode_one_hot(expected)
guess = decode_one_hot(prediction)
print('T:', correct)
print('G:', guess)
with open(sys.argv[1]) as f:
for line in f:
if line.isspace(): continue
onehots = encode_one_hot(line)
data = [[] for _ in range(LINE_SIZE)]
for i, c in enumerate(onehots):
data[i].append(c)
for j in range(len(onehots), LINE_SIZE):
data[j].append(np.zeros((INPUT_VOCAB_SIZE)))
inputs = [np.array(e) for e in data]
preds = model.predict(inputs)
normal = decode_one_hot(preds[0])
print(decode_one_hot(onehots))
print(normal)