correct_prediction=tf.equal(tf.argmax(y_predict,1),tf.argmax(y_actual,1)) accuracy=tf.reduce_mean(tf.cast(correct_prediction,'float'))
时间: 2023-10-08 12:12:16 浏览: 58
这是一个用于计算模型准确率的代码片段。其中,y_predict是模型的预测结果,y_actual是真实标签。tf.argmax()函数用于获取每个样本的预测结果和真实标签中概率最大的类别(即预测结果和真实标签的索引)。tf.equal()函数用于比较预测结果和真实标签是否一致,返回一个布尔类型的张量。tf.cast()函数用于将布尔类型的张量转换为浮点类型的张量。tf.reduce_mean()函数用于计算张量中所有元素的平均值,即准确率。最终,accuracy变量表示模型的准确率。
相关问题
import time import tensorflow.compat.v1 as tf tf.disable_v2_behavior() from tensorflow.examples.tutorials.mnist import input_data import mnist_inference import mnist_train tf.compat.v1.reset_default_graph() EVAL_INTERVAL_SECS = 10 def evaluate(mnist): with tf.Graph().as_default() as g: #定义输入与输出的格式 x = tf.compat.v1.placeholder(tf.float32, [None, mnist_inference.INPUT_NODE], name='x-input') y_ = tf.compat.v1.placeholder(tf.float32, [None, mnist_inference.OUTPUT_NODE], name='y-input') validate_feed = {x: mnist.validation.images, y_: mnist.validation.labels} #直接调用封装好的函数来计算前向传播的结果 y = mnist_inference.inference(x, None) #计算正确率 correcgt_prediction = tf.equal(tf.argmax(y, 1), tf.argmax(y_, 1)) accuracy = tf.reduce_mean(tf.cast(correcgt_prediction, tf.float32)) #通过变量重命名的方式加载模型 variable_averages = tf.train.ExponentialMovingAverage(0.99) variable_to_restore = variable_averages.variables_to_restore() saver = tf.train.Saver(variable_to_restore) #每隔10秒调用一次计算正确率的过程以检测训练过程中正确率的变化 while True: with tf.compat.v1.Session() as sess: ckpt = tf.train.get_checkpoint_state(minist_train.MODEL_SAVE_PATH) if ckpt and ckpt.model_checkpoint_path: #load the model saver.restore(sess, ckpt.model_checkpoint_path) global_step = ckpt.model_checkpoint_path.split('/')[-1].split('-')[-1] accuracy_score = sess.run(accuracy, feed_dict=validate_feed) print("After %s training steps, validation accuracy = %g" % (global_step, accuracy_score)) else: print('No checkpoint file found') return time.sleep(EVAL_INTERVAL_SECS) def main(argv=None): mnist = input_data.read_data_sets(r"D:\Anaconda123\Lib\site-packages\tensorboard\mnist", one_hot=True) evaluate(mnist) if __name__ == '__main__': tf.compat.v1.app.run()对代码进行改进
以下是对代码的改进建议:
1. 在代码开头添加注释,简要说明代码功能和使用方法。
2. 将导入模块的语句放在代码开头。
3. 将模型保存路径和评估时间间隔定义为常量,并使用有意义的变量名。
4. 将计算正确率和加载模型的过程封装为函数。
5. 在主函数中调用评估函数。
改进后的代码如下:
```
# 该代码实现了使用已训练好的模型对 MNIST 数据集进行评估
import time
import tensorflow.compat.v1 as tf
from tensorflow.examples.tutorials.mnist import input_data
import mnist_inference
import mnist_train
# 定义常量
MODEL_SAVE_PATH = 'model/'
EVAL_INTERVAL_SECS = 10
def evaluate(mnist):
"""
计算模型在验证集上的正确率
"""
with tf.Graph().as_default() as g:
# 定义输入和输出格式
x = tf.placeholder(tf.float32, [None, mnist_inference.INPUT_NODE], name='x-input')
y_ = tf.placeholder(tf.float32, [None, mnist_inference.OUTPUT_NODE], name='y-input')
# 直接调用封装好的函数计算前向传播结果
y = mnist_inference.inference(x, None)
# 计算正确率
correct_prediction = tf.equal(tf.argmax(y, 1), tf.argmax(y_, 1))
accuracy = tf.reduce_mean(tf.cast(correct_prediction, tf.float32))
# 加载模型
variable_averages = tf.train.ExponentialMovingAverage(mnist_train.MOVING_AVERAGE_DECAY)
variables_to_restore = variable_averages.variables_to_restore()
saver = tf.train.Saver(variables_to_restore)
# 在验证集上计算正确率
with tf.Session() as sess:
ckpt = tf.train.get_checkpoint_state(MODEL_SAVE_PATH)
if ckpt and ckpt.model_checkpoint_path:
saver.restore(sess, ckpt.model_checkpoint_path)
global_step = ckpt.model_checkpoint_path.split('/')[-1].split('-')[-1]
accuracy_score = sess.run(accuracy, feed_dict={x: mnist.validation.images, y_: mnist.validation.labels})
print("After %s training steps, validation accuracy = %g" % (global_step, accuracy_score))
else:
print('No checkpoint file found')
def main(argv=None):
# 读取数据集
mnist = input_data.read_data_sets('MNIST_data', one_hot=True)
# 每隔一定时间评估模型在验证集上的正确率
while True:
evaluate(mnist)
time.sleep(EVAL_INTERVAL_SECS)
if __name__ == '__main__':
tf.app.run()
```
model = tf.keras.models.Sequential([ tf.keras.layers.Dense(64, activation='relu'), tf.keras.layers.Dense(10) ]) sample_input = tf.ones((1, input_shape)) sample_output = model(sample_input) loss = tf.sqrt(tf.reduce_mean(tf.square(prediction-ys))) var_list = model.trainable_variables train_step = tf.keras.optimizers.SGD(0.9).minimize(loss, var_list=var_list)出现这个错误怎么改NameError: name 'input_shape' is not defined
这个错误是因为代码中使用了一个未定义的变量 "input_shape"。你需要在代码中定义变量 "input_shape" 并赋值,例如:
```
input_shape = 10 # 假设输入的形状为 (1, 10)
model = tf.keras.models.Sequential([
tf.keras.layers.Dense(64, activation='relu'),
tf.keras.layers.Dense(10)
])
sample_input = tf.ones((1, input_shape))
sample_output = model(sample_input)
loss = tf.sqrt(tf.reduce_mean(tf.square(prediction-ys)))
var_list = model.trainable_variables
train_step = tf.keras.optimizers.SGD(0.9).minimize(loss, var_list=var_list)
```
在这个例子中,我们假设输入的形状是 (1, 10),并将其赋值给了变量 "input_shape"。你需要根据实际情况修改该变量的赋值。