我确实是 tensorflow 以及所有该领域的初学者，但我已经看过 Andrej Karpathy 在 CS231n 类(class)中的所有讲座，所以我理解代码。
# Implementing an RNN in TensorFlow
# ----------------------------------
#
# We implement an RNN in TensorFlow to predict spam/ham from texts
#
# https://github.com/nfmcclure/tensorflow_cookbook/blob/master/09_Recurrent_Neural_Networks/02_Implementing_RNN_for_Spam_Prediction/02_implementing_rnn.py
import os
import re
import io
import glob
import requests
import numpy as np
import matplotlib.pyplot as plt
import tensorflow as tf
from zipfile import ZipFile
from tensorflow.python.framework import ops
ops.reset_default_graph()
# Start a graph
sess = tf.Session()
# Set RNN parameters
epochs = 20
batch_size = 250
max_sequence_length = 25
rnn_size = 10
embedding_size = 50
min_word_frequency = 10
learning_rate = 0.0005
dropout_keep_prob = tf.placeholder(tf.float32)
# Download or open data
data_dir = 'temp'
data_file = 'text_data.txt'
if not os.path.exists(data_dir):
os.makedirs(data_dir)
if not os.path.isfile(os.path.join(data_dir, data_file)):
zip_url = 'http://archive.ics.uci.edu/ml/machine-learning-databases/00228/smsspamcollection.zip'
r = requests.get(zip_url)
z = ZipFile(io.BytesIO(r.content))
file = z.read('SMSSpamCollection')
# Format Data
text_data = file.decode()
text_data = text_data.encode('ascii', errors='ignore')
text_data = text_data.decode().split('\n')
# Save data to text file
with open(os.path.join(data_dir, data_file), 'w') as file_conn:
for text in text_data:
file_conn.write("{}\n".format(text))
else:
# Open data from text file
text_data = []
with open(os.path.join(data_dir, data_file), 'r') as file_conn:
for row in file_conn:
text_data.append(row)
text_data = text_data[:-1]
text_data = [x.split('\t') for x in text_data if len(x) >= 1]
text_data = [x for x in text_data if len(x) > 1]
print([list(x) for x in zip(*text_data)])
[text_data_target, text_data_train] = [list(x) for x in zip(*text_data)]
# Create a text cleaning function
def clean_text(text_string):
text_string = re.sub(r'([^\s\w]|_|[0-9])+', '', text_string)
text_string = " ".join(text_string.split())
text_string = text_string.lower()
return (text_string)
# Clean texts
text_data_train = [clean_text(x) for x in text_data_train]
# Change texts into numeric vectors
vocab_processor = tf.contrib.learn.preprocessing.VocabularyProcessor(max_sequence_length,
min_frequency=min_word_frequency)
text_processed = np.array(list(vocab_processor.fit_transform(text_data_train)))
# Shuffle and split data
text_processed = np.array(text_processed)
text_data_target = np.array([1 if x == 'ham' else 0 for x in text_data_target])
shuffled_ix = np.random.permutation(np.arange(len(text_data_target)))
x_shuffled = text_processed[shuffled_ix]
y_shuffled = text_data_target[shuffled_ix]
# Split train/test set
ix_cutoff = int(len(y_shuffled) * 0.80)
x_train, x_test = x_shuffled[:ix_cutoff], x_shuffled[ix_cutoff:]
y_train, y_test = y_shuffled[:ix_cutoff], y_shuffled[ix_cutoff:]
vocab_size = len(vocab_processor.vocabulary_)
print("Vocabulary Size: {:d}".format(vocab_size))
print("80-20 Train Test split: {:d} -- {:d}".format(len(y_train), len(y_test)))
# Create placeholders
x_data = tf.placeholder(tf.int32, [None, max_sequence_length])
y_output = tf.placeholder(tf.int32, [None])
# Create embedding
embedding_mat = tf.Variable(tf.random_uniform([vocab_size, embedding_size], -1.0, 1.0))
embedding_output = tf.nn.embedding_lookup(embedding_mat, x_data)
# embedding_output_expanded = tf.expand_dims(embedding_output, -1)
# Define the RNN cell
# tensorflow change >= 1.0, rnn is put into tensorflow.contrib directory. Prior version not test.
if tf.__version__[0] >= '1':
cell = tf.contrib.rnn.BasicRNNCell(num_units=rnn_size)
else:
cell = tf.nn.rnn_cell.BasicRNNCell(num_units=rnn_size)
output, state = tf.nn.dynamic_rnn(cell, embedding_output, dtype=tf.float32)
output = tf.nn.dropout(output, dropout_keep_prob)
# Get output of RNN sequence
output = tf.transpose(output, [1, 0, 2])
last = tf.gather(output, int(output.get_shape()[0]) - 1)
weight = tf.Variable(tf.truncated_normal([rnn_size, 2], stddev=0.1))
bias = tf.Variable(tf.constant(0.1, shape=[2]))
logits_out = tf.matmul(last, weight) + bias
# Loss function
losses = tf.nn.sparse_softmax_cross_entropy_with_logits(logits=logits_out,
labels=y_output) # logits=float32, labels=int32
loss = tf.reduce_mean(losses)
accuracy = tf.reduce_mean(tf.cast(tf.equal(tf.argmax(logits_out, 1), tf.cast(y_output, tf.int64)), tf.float32))
optimizer = tf.train.RMSPropOptimizer(learning_rate)
train_step = optimizer.minimize(loss)
init = tf.global_variables_initializer()
sess.run(init)
train_loss = []
test_loss = []
train_accuracy = []
test_accuracy = []
# Start training
for epoch in range(epochs):
# Shuffle training data
shuffled_ix = np.random.permutation(np.arange(len(x_train)))
x_train = x_train[shuffled_ix]
y_train = y_train[shuffled_ix]
num_batches = int(len(x_train) / batch_size) + 1
# TO DO CALCULATE GENERATIONS ExACTLY
for i in range(num_batches):
# Select train data
min_ix = i * batch_size
max_ix = np.min([len(x_train), ((i + 1) * batch_size)])
x_train_batch = x_train[min_ix:max_ix]
y_train_batch = y_train[min_ix:max_ix]
# Run train step
train_dict = {x_data: x_train_batch, y_output: y_train_batch, dropout_keep_prob: 0.5}
sess.run(train_step, feed_dict=train_dict)
# Run loss and accuracy for training
temp_train_loss, temp_train_acc = sess.run([loss, accuracy], feed_dict=train_dict)
train_loss.append(temp_train_loss)
train_accuracy.append(temp_train_acc)
# Run Eval Step
test_dict = {x_data: x_test, y_output: y_test, dropout_keep_prob: 1.0}
temp_test_loss, temp_test_acc = sess.run([loss, accuracy], feed_dict=test_dict)
test_loss.append(temp_test_loss)
test_accuracy.append(temp_test_acc)
print('Epoch: {}, Test Loss: {:.2}, Test Acc: {:.2}'.format(epoch + 1, temp_test_loss, temp_test_acc))
# Plot loss over time
epoch_seq = np.arange(1, epochs + 1)
plt.plot(epoch_seq, train_loss, 'k--', label='Train Set')
plt.plot(epoch_seq, test_loss, 'r-', label='Test Set')
plt.title('Softmax Loss')
plt.xlabel('Epochs')
plt.ylabel('Softmax Loss')
plt.legend(loc='upper left')
plt.show()
# Plot accuracy over time
plt.plot(epoch_seq, train_accuracy, 'k--', label='Train Set')
plt.plot(epoch_seq, test_accuracy, 'r-', label='Test Set')
plt.title('Test Accuracy')
plt.xlabel('Epochs')
plt.ylabel('Accuracy')
plt.legend(loc='upper left')
plt.show()
def findFiles(path): return glob.glob(path)
pred_array = "words"
pred_num = np.array(list(vocab_processor.fit_transform(pred_array)))
print(pred_num)
pred_output = tf.placeholder(tf.float32,[1,len(pred_array),max_sequence_length])
feed_dict = {pred_output: [pred_num]}
classification = sess.run(losses, feed_dict)
print(classification)
这是一个 RNN 垃圾邮件分类器，并且运行良好(接受我在最后编写的尝试创建预测的部分)。
我只是想了解如何创建一个预测函数，看起来像这样:
def predict(text): # text is a string (my mail)
# Doing prediction stuff
return (top result) # ham or spam
最后几行是我最后一次尝试，但出现以下错误:
tensorflow.python.framework.errors_impl.InvalidArgumentError: You must feed a value for placeholder tensor 'Placeholder' with dtype float
[[Node: Placeholder = Placeholder[dtype=DT_FLOAT, shape=<unknown>, _device="/job:localhost/replica:0/task:0/cpu:0"]()]]
我还尝试使用 Making predictions with a TensorFlow model 做一些事情，我还读过 https://www.tensorflow.org/serving/serving_basic我尝试过的每件事都失败了......
由于我只是初学者，欢迎解释，但我不确定我是否知道如何编码，所以您能否也发布代码答案。
(Python 3.6 顺便说一句)
谢谢!
最佳答案
如果您查看原始代码如何执行训练和测试步骤，特别是它们如何设置 train_dict 和 test_dict，您会发现它们将值提供给每个图中定义为占位符的张量。基本上，如果占位符要用于您要求网络执行的任何计算，则需要为其赋予一些值。由于您正在寻找来自网络的预测，因此您可能不需要提供预期的输出，但您需要为其提供输入数据x_data以及dropout_keep_prob的值>。用于预测的值应为 dropout_keep_prob=1.0。
您还需要一个预测，而不是网络丢失。损失基本上是衡量网络的输出与您的预期相差多远的指标，但由于您试图预测新数据的某些内容，因此您实际上只想看看网络的输出是什么。您可以直接使用 logits_out 操作来完成此操作，或者我们可以添加一个操作，将您的 logits 转换为类的概率分布。无论哪种方式，您都可以查看分布以了解网络认为您的数据属于每个类别的可能性有多大，或者您可以采用该向量的最大值来输出网络的最佳猜测。
所以你可以尝试这样的事情:
prediction = tf.nn.softmax(logits_out)
feed_dict = {x_data: your_input_data, dropout_keep_prob: 1.0}
pred = sess.run(prediction, feed_dict)
best_guess = np.argmax(pred) # highest-rated class
关于python - 使用 tensorflow 进行预测，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/46104783/