TensorBoard可视化
import tensorflow as tf # 定义命名空间 with tf.name_scope('input'): # fetch:就是同时运行多个op的意思 # 定义名称,会在tensorboard中代替显示 input1 = tf.constant(3.0,name='A') input2 = tf.constant(4.0,name='B') input3 = tf.constant(5.0,name='C') with tf.name_scope('op'): #加法 add = tf.add(input2,input3) #乘法 mul = tf.multiply(input1,add) with tf.Session() as ss: #默认在当前py目录下的logs文件夹,没有会自己创建 result = ss.run([mul,add]) wirter = tf.summary.FileWriter('logs/demo/',ss.graph) print(result)
[27.0, 9.0]
这段代码主要演示了如何使用TensorFlow和TensorBoard创建和可视化计算图。
TensorFlow是一个基于数据流图进行数值计算的开源软件库,具有快速的计算速度和灵活的构建方式,被广泛应用于机器学习、深度学习等领域。而TensorBoard是TensorFlow提供的一个可视化工具,可以帮助开发者更好地理解、调试和优化TensorFlow中的计算图。
在这段代码中,首先通过tf.constant方法创建了三个常量input1、input2和input3,分别赋值为3.0、4.0和5.0,并给这些常量取了一个别名,分别为“A”、“B”和“C”,这样在后续的TensorBoard中我们就可以清晰地看到它们之间的关系。
接着,使用tf.add和tf.multiply方法分别定义了加法和乘法操作,其中加法使用了input2和input3,乘法使用了input1和加法的结果。在这里也定义了两个命名空间input和op,分别代表输入和操作的过程。
然后,使用with tf.Session() as ss:创建一个会话,用ss.run方法来运行计算图,并将结果保存在result中。
最后,使用tf.summary.FileWriter方法将计算图写入到logs/demo/目录下,以便在TensorBoard中查看。运行python 文件名.py后,在命令行中输入tensorboard --logdir=logs/demo启动TensorBoard服务,打开浏览器,输入http://localhost:6006/即可访问TensorBoard的可视化界面。
在TensorBoard界面中,可以查看到计算图的可视化结构、常量的取值、操作的过程等信息,帮助开发者更好地理解、调试和优化TensorFlow的计算图。
TensorBoard案例
#!/usr/bin/env python # -*- coding: utf-8 -*- from __future__ import absolute_import from __future__ import division from __future__ import print_function import argparse import sys import os import tensorflow as tf import warnings warnings.filterwarnings("ignore") from tensorflow.examples.tutorials.mnist import input_data max_steps = 200 # 最大迭代次数 默认1000 learning_rate = 0.001 # 学习率 dropout = 0.9 # dropout时随机保留神经元的比例 data_dir = os.path.join('data', 'mnist')# 样本数据存储的路径 if not os.path.exists('log'): os.mkdir('log') log_dir = 'log' # 输出日志保存的路径 mnist = input_data.read_data_sets("MNIST_data",one_hot=True) sess = tf.InteractiveSession() with tf.name_scope('input'): x = tf.placeholder(tf.float32, [None, 784], name='x-input') y_ = tf.placeholder(tf.float32, [None, 10], name='y-input') #使用tf.summary.image保存图像信息,在tensorboard上还原出输入的特征数据对应的图片 with tf.name_scope('input_reshape'): image_shaped_input = tf.reshape(x, [-1, 28, 28, 1]) tf.summary.image('input', image_shaped_input, 10) def weight_variable(shape): """Create a weight variable with appropriate initialization.""" initial = tf.truncated_normal(shape, stddev=0.1) return tf.Variable(initial) def bias_variable(shape): """Create a bias variable with appropriate initialization.""" initial = tf.constant(0.1, shape=shape) return tf.Variable(initial) def variable_summaries(var): """Attach a lot of summaries to a Tensor (for TensorBoard visualization).""" with tf.name_scope('summaries'): # 计算参数的均值,并使用tf.summary.scaler记录 mean = tf.reduce_mean(var) tf.summary.scalar('mean', mean) # 计算参数的标准差 with tf.name_scope('stddev'): stddev = tf.sqrt(tf.reduce_mean(tf.square(var - mean))) # 使用tf.summary.scaler记录记录下标准差,最大值,最小值 tf.summary.scalar('stddev', stddev) tf.summary.scalar('max', tf.reduce_max(var)) tf.summary.scalar('min', tf.reduce_min(var)) # 用直方图记录参数的分布 tf.summary.histogram('histogram', var) """ 构建神经网络层 创建第一层隐藏层 创建一个构建隐藏层的方法,输入的参数有: input_tensor:特征数据 input_dim:输入数据的维度大小 output_dim:输出数据的维度大小(=隐层神经元个数) layer_name:命名空间 act=tf.nn.relu:激活函数(默认是relu) """ def nn_layer(input_tensor, input_dim, output_dim, layer_name, act=tf.nn.relu): """Reusable code for making a simple neural net layer. It does a matrix multiply, bias add, and then uses relu to nonlinearize. It also sets up name scoping so that the resultant graph is easy to read, and adds a number of summary ops. """ # 设置命名空间 with tf.name_scope(layer_name): # 调用之前的方法初始化权重w,并且调用参数信息的记录方法,记录w的信息 with tf.name_scope('weights'): weights = weight_variable([input_dim, output_dim]) #神经元数量 variable_summaries(weights) # 调用之前的方法初始化权重b,并且调用参数信息的记录方法,记录b的信息 with tf.name_scope('biases'): biases = bias_variable([output_dim]) variable_summaries(biases) # 执行wx+b的线性计算,并且用直方图记录下来 with tf.name_scope('linear_compute'): preactivate = tf.matmul(input_tensor, weights) + biases tf.summary.histogram('linear', preactivate) # 将线性输出经过激励函数,并将输出也用直方图记录下来 activations = act(preactivate, name='activation') tf.summary.histogram('activations', activations) # 返回激励层的最终输出 return activations hidden1 = nn_layer(x, 784, 500, 'layer1') """ 创建一个dropout层,,随机关闭掉hidden1的一些神经元,并记录keep_prob """ with tf.name_scope('dropout'): keep_prob = tf.placeholder(tf.float32) tf.summary.scalar('dropout_keep_probability', keep_prob) dropped = tf.nn.dropout(hidden1, keep_prob) """ 创建一个输出层,输入的维度是上一层的输出:500,输出的维度是分类的类别种类:10, 激活函数设置为全等映射identity.(暂且先别使用softmax,会放在之后的损失函数中一起计算) """ y = nn_layer(dropped, 500, 10, 'layer2', act=tf.identity) """ 创建损失函数 使用tf.nn.softmax_cross_entropy_with_logits来计算softmax并计算交叉熵损失,并且求均值作为最终的损失值。 """ with tf.name_scope('loss'): # 计算交叉熵损失(每个样本都会有一个损失) diff = tf.nn.softmax_cross_entropy_with_logits(labels=y_, logits=y) with tf.name_scope('total'): # 计算所有样本交叉熵损失的均值 cross_entropy = tf.reduce_mean(diff) tf.summary.scalar('loss', cross_entropy) """ 训练,并计算准确率 使用AdamOptimizer优化器训练模型,最小化交叉熵损失 计算准确率,并用tf.summary.scalar记录准确率 """ with tf.name_scope('train'): train_step = tf.train.AdamOptimizer(learning_rate).minimize( cross_entropy) with tf.name_scope('accuracy'): with tf.name_scope('correct_prediction'): # 分别将预测和真实的标签中取出最大值的索引,弱相同则返回1(true),不同则返回0(false) correct_prediction = tf.equal(tf.argmax(y, 1), tf.argmax(y_, 1)) with tf.name_scope('accuracy'): # 求均值即为准确率 accuracy = tf.reduce_mean(tf.cast(correct_prediction, tf.float32)) tf.summary.scalar('accuracy', accuracy) # summaries合并 merged = tf.summary.merge_all() # 写到指定的磁盘路径中 #删除src路径下所有文件 def delete_file_folder(src): '''delete files and folders''' if os.path.isfile(src): try: os.remove(src) except: pass elif os.path.isdir(src): for item in os.listdir(src): itemsrc=os.path.join(src,item) delete_file_folder(itemsrc) try: os.rmdir(src) except: pass #删除之前生成的log if os.path.exists(log_dir + '/train'): delete_file_folder(log_dir + '/train') if os.path.exists(log_dir + '/test'): delete_file_folder(log_dir + '/test') train_writer = tf.summary.FileWriter(log_dir + '/train', sess.graph) test_writer = tf.summary.FileWriter(log_dir + '/test') # 运行初始化所有变量 tf.global_variables_initializer().run() #现在我们要获取之后要喂入的数据 def feed_dict(train): """Make a TensorFlow feed_dict: maps data onto Tensor placeholders.""" if train: xs, ys = mnist.train.next_batch(100) k = dropout else: xs, ys = mnist.test.images, mnist.test.labels k = 1.0 return {x: xs, y_: ys, keep_prob: k} """ 开始训练模型。 每隔10步,就进行一次merge, 并打印一次测试数据集的准确率, 然后将测试数据集的各种summary信息写进日志中。 每隔100步,记录原信息 其他每一步时都记录下训练集的summary信息并写到日志中。 """ for i in range(max_steps): if i % 10 == 0: # 记录测试集的summary与accuracy summary, acc = sess.run([merged, accuracy], feed_dict=feed_dict(False)) test_writer.add_summary(summary, i) print('Accuracy at step %s: %s' % (i, acc)) else: # 记录训练集的summary if i % 100 == 99: # Record execution stats run_options = tf.RunOptions(trace_level=tf.RunOptions.FULL_TRACE) run_metadata = tf.RunMetadata() summary, _ = sess.run([merged, train_step], feed_dict=feed_dict(True), options=run_options, run_metadata=run_metadata) train_writer.add_run_metadata(run_metadata, 'step%03d' % i) train_writer.add_summary(summary, i) print('Adding run metadata for', i) else: # Record a summary summary, _ = sess.run([merged, train_step], feed_dict=feed_dict(True)) train_writer.add_summary(summary, i) train_writer.close() test_writer.close()
WARNING:tensorflow:From <ipython-input-3-27b4be5f38e0>:25: read_data_sets (from tensorflow.contrib.learn.python.learn.datasets.mnist) is deprecated and will be removed in a future version. Instructions for updating: Please use alternatives such as official/mnist/dataset.py from tensorflow/models. WARNING:tensorflow:From /home/nlp/anaconda3/lib/python3.7/site-packages/tensorflow/contrib/learn/python/learn/datasets/mnist.py:260: maybe_download (from tensorflow.contrib.learn.python.learn.datasets.base) is deprecated and will be removed in a future version. Instructions for updating: Please write your own downloading logic. WARNING:tensorflow:From /home/nlp/anaconda3/lib/python3.7/site-packages/tensorflow/contrib/learn/python/learn/datasets/mnist.py:262: extract_images (from tensorflow.contrib.learn.python.learn.datasets.mnist) is deprecated and will be removed in a future version. Instructions for updating: Please use tf.data to implement this functionality. Extracting MNIST_data/train-images-idx3-ubyte.gz WARNING:tensorflow:From /home/nlp/anaconda3/lib/python3.7/site-packages/tensorflow/contrib/learn/python/learn/datasets/mnist.py:267: extract_labels (from tensorflow.contrib.learn.python.learn.datasets.mnist) is deprecated and will be removed in a future version. Instructions for updating: Please use tf.data to implement this functionality. Extracting MNIST_data/train-labels-idx1-ubyte.gz WARNING:tensorflow:From /home/nlp/anaconda3/lib/python3.7/site-packages/tensorflow/contrib/learn/python/learn/datasets/mnist.py:110: dense_to_one_hot (from tensorflow.contrib.learn.python.learn.datasets.mnist) is deprecated and will be removed in a future version. Instructions for updating: Please use tf.one_hot on tensors. Extracting MNIST_data/t10k-images-idx3-ubyte.gz Extracting MNIST_data/t10k-labels-idx1-ubyte.gz WARNING:tensorflow:From /home/nlp/anaconda3/lib/python3.7/site-packages/tensorflow/contrib/learn/python/learn/datasets/mnist.py:290: DataSet.__init__ (from tensorflow.contrib.learn.python.learn.datasets.mnist) is deprecated and will be removed in a future version. Instructions for updating: Please use alternatives such as official/mnist/dataset.py from tensorflow/models. WARNING:tensorflow:From <ipython-input-3-27b4be5f38e0>:109: calling dropout (from tensorflow.python.ops.nn_ops) with keep_prob is deprecated and will be removed in a future version. Instructions for updating: Please use `rate` instead of `keep_prob`. Rate should be set to `rate = 1 - keep_prob`. WARNING:tensorflow:From <ipython-input-3-27b4be5f38e0>:123: softmax_cross_entropy_with_logits (from tensorflow.python.ops.nn_ops) is deprecated and will be removed in a future version. Instructions for updating: Future major versions of TensorFlow will allow gradients to flow into the labels input on backprop by default. See `tf.nn.softmax_cross_entropy_with_logits_v2`. Accuracy at step 0: 0.0639 Accuracy at step 10: 0.7139 Accuracy at step 20: 0.8271 Accuracy at step 30: 0.8647 Accuracy at step 40: 0.8818 Accuracy at step 50: 0.8932 Accuracy at step 60: 0.8984 Accuracy at step 70: 0.8986 Accuracy at step 80: 0.9062 Accuracy at step 90: 0.9128 Adding run metadata for 99 Accuracy at step 100: 0.9134 Accuracy at step 110: 0.9212 Accuracy at step 120: 0.9156 Accuracy at step 130: 0.9226 Accuracy at step 140: 0.9251 Accuracy at step 150: 0.9238 Accuracy at step 160: 0.9259 Accuracy at step 170: 0.9265 Accuracy at step 180: 0.9291 Accuracy at step 190: 0.932 Adding run metadata for 199
这段代码主要演示了如何使用Tensorflow和TensorBoard创建和可视化卷积神经网络(CNN)。
CNN是一种深度学习结构,是神经网络中的一种,可以应用于图像识别、语音识别等领域。在这段代码中,我们将使用CNN完成MNIST手写数字识别任务,输入为28×28像素的手写数字图像,输出为0-9其中一种数字的概率。
首先,通过tf.placeholder方法创建了两个placeholder变量x和y_,分别表示网络的输入和输出。在输入数据的处理上,为了将输入数据(28×28个像素点)可视化,使用了tf.summary.image记录了图像信息,用reshape方法将输入特征数据进行重构,确保输入的图像是28×28×1的大小,并用tf.summary.image将其记录下来。
其次,在神经网络的构建方面,我们创建了两个隐藏层和一个输出层。其中,每一个隐藏层都包含一个线性计算层和一个ReLU激活函数层,并用tf.summary.histogram方法记录下每一层的相关参数,以便在TensorBoard中查看各个层的变化。
然后,我们在第一个隐藏层后加入了dropout层,随机关闭掉一定比例的神经元,以避免过拟合。在输出层中,使用tf.nn.softmax cross_entropy_with_logits计算交叉熵损失,并用tf.summary.scalar方法记录损失信息。我们使用tf.train.AdamOptimizer训练模型,并使用tf.reduce_mean(tf.cast(correct_prediction, tf.float32))计算准确率,并用tf.summary.scalar记录准确率信息。
最后,我们定义了merged变量,将所有需要记录下来的信息汇总在一起,并通过tf.summary.merge_all()的方法全部合并,最后通过tf.summary.FileWriter方法将所有的信息写入到日志文件中。在训练过程中,每隔10步就记录下测试集的准确率和相关信息,并记录到日志中;每隔100步记录下训练集的原信息,并记录到日志中;其他步数记录训练集的summary以及写入到日志中。最终,通过train_writer.close()和test_writer.close()关闭日志文件。
整个代码中,命名空间的使用规范,各个参数的记录方式清晰明了,使得我们在TensorBoard中能够清晰地了解每一层的参数变化、loss的变化、准确率的变化等。因此,TensorBoard能够很好地帮助开发者进行模型的调试、分析和优化。