使用softmax进行张量流文本分类

时间:2018-01-23 22:59:03

标签: tensorflow machine-learning multilabel-classification softmax

我对张量流和机器学习都很陌生,我正在使用安然数据集对十大发件人进行分类。我在kaggle中发现了一些使用scikit-learn的好例子,但是当我尝试使用张量流时,准确度就差得很大。

以下是我正在做的事情

  • 加载安然数据集
  • 获取前10名发件人的数据
  • 执行10个发件人的tf-idf矢量化
  • 将数据拆分为培训和测试集
  • 定义模型(tf.matmul(X_train_dataset,权重))+偏差和损失函数(tf.nn.softmax_cross_entropy_with_logits)
  • 训练模型
  • 输出测试精度

我无法弄清楚我做错了什么。任何有关这方面的见解都会非常有用。

以下是整个代码,我使用https://github.com/jupyter/docker-stacks/tree/master/tensorflow-notebook运行它,加载enron的代码和清理enron数据集来自kaggle示例(https://www.kaggle.com/yaroshevskiy/enron-top-10-senders-classification)和培训数据集可以在https://www.kaggle.com/yaroshevskiy/enron-top-10-senders-classification/data找到。

import tensorflow as tf
import matplotlib.pyplot as plt
import csv
import numpy as np
import os
import string
import requests
import io
import nltk
from zipfile import ZipFile
from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.feature_extraction.text import HashingVectorizer
from tensorflow.python.framework import ops
import pandas as pd
import re
import email

ops.reset_default_graph()

num_labels = 10
batch_size = 200
max_features = 1000
learning_rate = 0.05
num_steps = 10000

def email_from_string(raw_email):
    msg = email.message_from_string(raw_email)

    content = []
    for part in msg.walk():
        if part.get_content_type() == 'text/plain':
            content.append(part.get_payload())

    result = {}
    for key in msg.keys():
        result[key] = msg[key]
    result["content"] = ''.join(content)

    return result

def content_to_wordlist( content, remove_stopwords=False ):
    content = re.sub("[^a-zA-Z]"," ", content)
    words = content.lower().split()
    return ' '.join(words)

def setup_enron():
    # Read the emails from csv
    enron_data = pd.read_csv("emails.csv", header=0, quoting=2)
    enron_sent = enron_data[enron_data["file"].str.contains('sent').tolist()]
    enron_sent = enron_sent.assign(sender=enron_sent["file"].map(lambda x: re.search("(.*)/.*sent", x).group(1)).values)
    enron_sent.drop("file", axis=1, inplace=True)

    # Get the top senders based on the number of labels
    top_senders = enron_sent["sender"].value_counts().head(num_labels).index.values
    mapping = dict(zip(top_senders, range(num_labels)))
    enron_sent = enron_sent[enron_sent.sender.isin(top_senders)]

    enron_parsed = pd.DataFrame(list(map(email_from_string, enron_sent.message)))

    data = pd.DataFrame(list(map(content_to_wordlist,
                      enron_parsed[['Subject', 'content']].apply(lambda x: ' '.join(x), axis=1))),
                      columns = ["content"])

    data = data.assign(sender=enron_sent["sender"].values)
    data = data.replace({'sender': mapping})

    # Perform tfidf vectorization
    tfidf = TfidfVectorizer(sublinear_tf=True, max_df=0.5, stop_words='english', max_features=max_features)
    sparse_tfidf_texts = tfidf.fit_transform(data["content"].values.tolist())
    text_enron = data["content"].values.tolist()
    target_enron = data["sender"].values.tolist()

    # one hot vector
    enron_y = np.zeros((len(target_enron), 10), dtype=np.float32)
    for i in range(len(target_enron)):
        enron_y[i, target_enron[i]] = 1.0

    # split the data sets into train and test
    train_indices = np.random.choice(sparse_tfidf_texts.shape[0], round(0.8*sparse_tfidf_texts.shape[0]), replace=False)
    test_indices = np.array(list(set(range(sparse_tfidf_texts.shape[0])) - set(train_indices)))
    texts_train = sparse_tfidf_texts[train_indices]
    texts_test = sparse_tfidf_texts[test_indices]
    train_y = np.array([x for ix, x in enumerate(enron_y) if ix in train_indices])
    test_y = np.array([x for ix, x in enumerate(enron_y) if ix in test_indices])

    return texts_train, texts_test, train_y, test_y

def accuracy(predictions, labels):
    correctly_predicted = np.sum(np.argmax(predictions, 1) == np.argmax(labels, 1))
    return (100.0 * correctly_predicted) / predictions.shape[0]

def start_tensorflow(train_dataset, test_dataset, train_labels, test_labels):
    graph = tf.Graph()

    with graph.as_default():
            X_train_dataset = tf.placeholder(tf.float32, shape=(batch_size, max_features))
            Y_train_dataset = tf.placeholder(tf.float32, shape=(batch_size, num_labels))
            X_test_dataset = tf.constant(test_dataset.todense(), dtype=tf.float32)
            Y_test_dataset = tf.constant(test_labels, dtype=tf.float32)

            # Variables
            weights = tf.Variable(tf.truncated_normal([max_features, num_labels]))
            biases = tf.Variable(tf.zeros([num_labels]), dtype=tf.float32)

            # Training computation
            logits = tf.matmul(X_train_dataset, weights) + biases
            loss = tf.reduce_mean(tf.nn.softmax_cross_entropy_with_logits(
                                    labels=Y_train_dataset, logits=logits))

            # Optimizer
            optimizer = tf.train.GradientDescentOptimizer(learning_rate).minimize(loss)

            # Predictions
            train_prediction = tf.nn.softmax(logits)
            test_prediction = tf.nn.softmax(tf.matmul(X_test_dataset, weights) + biases)

            with tf.Session(graph=graph) as sess:
                    tf.global_variables_initializer().run()
                    print("Initialized")

                    for step in range(num_steps):
                            offset = np.random.randint(0, train_labels.shape[0] - batch_size - 1)
                            # Generate a batch
                            batch_data = train_dataset[offset:(offset + batch_size), :].todense()
                            batch_labels = train_labels[offset:(offset + batch_size), :]

                            feed_dict = {X_train_dataset: batch_data, Y_train_dataset: batch_labels}

                            _, l, predictions = sess.run([optimizer, loss, train_prediction],
                                                            feed_dict=feed_dict)

                            if (step % 500 == 0):
                                    print("Batch loss step: {0}: {1}".format(step, l))
                                    print("Batch accuracy: {:.1f}%".format(accuracy(predictions, batch_labels)))
                                    print("Test Accuracy: {:.1f}%".format(accuracy(test_prediction.eval(), test_labels)))

if __name__ == "__main__":
    x_train, x_test, y_train, y_test = setup_enron()
    start_tensorflow(x_train, x_test, y_train, y_test)

以下是输出

Generation # 500. Train Loss (Test Loss): 2.27 (2.28). Train Acc(Test Acc): 0.18 (0.19)
Generation # 1000. Train Loss (Test Loss): 2.27 (2.26). Train Acc(Test Acc): 0.18 (0.19)
Generation # 1500. Train Loss (Test Loss): 2.26 (2.24). Train Acc (Test Acc): 0.18 (0.19)
Generation # 2000. Train Loss (Test Loss): 2.22 (2.23). Train Acc (Test Acc): 0.21 (0.19)
Generation # 2500. Train Loss (Test Loss): 2.22 (2.22). Train Acc (Test Acc): 0.21 (0.19)
Generation # 3000. Train Loss (Test Loss): 2.21 (2.22). Train Acc (Test Acc): 0.20 (0.19)
Generation # 3500. Train Loss (Test Loss): 2.25 (2.21). Train Acc (Test Acc): 0.16 (0.19)
Generation # 4000. Train Loss (Test Loss): 2.19 (2.21). Train Acc (Test Acc): 0.24 (0.19)
Generation # 4500. Train Loss (Test Loss): 2.22 (2.21). Train Acc (Test Acc): 0.18 (0.19)
Generation # 5000. Train Loss (Test Loss): 2.18 (2.20). Train Acc (Test Acc): 0.22 (0.19)
Generation # 5500. Train Loss (Test Loss): 2.16 (2.20). Train Acc (Test Acc): 0.25 (0.19)
Generation # 6000. Train Loss (Test Loss): 2.23 (2.20). Train Acc (Test Acc): 0.18 (0.19)
Generation # 6500. Train Loss (Test Loss): 2.22 (2.20). Train Acc (Test Acc): 0.18 (0.19)
Generation # 7000. Train Loss (Test Loss): 2.21 (2.20). Train Acc (Test Acc): 0.16 (0.19)
Generation # 7500. Train Loss (Test Loss): 2.16 (2.20). Train Acc (Test Acc): 0.20 (0.19)
Generation # 8000. Train Loss (Test Loss): 2.25 (2.20). Train Acc (Test Acc): 0.13 (0.19)
Generation # 8500. Train Loss (Test Loss): 2.18 (2.20). Train Acc (Test Acc): 0.21 (0.19)
Generation # 9000. Train Loss (Test Loss): 2.22 (2.20). Train Acc (Test Acc): 0.16 (0.19)
Generation # 9500. Train Loss (Test Loss): 2.19 (2.20). Train Acc (Test Acc): 0.16 (0.19)
Generation # 10000. Train Loss (Test Loss): 2.27 (2.20). Train Acc (Test Acc): 0.16 (0.19)     

0 个答案:

没有答案
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