a closed walk

A walk is a path in a graph that starts and ends at the same vertex, and visits each vertex along the way. In other words, it forms a loop or a cycle. The length of a closed walk is the number of edges it contains. A closed walk can be simple or non-simple, depending on whether it visits each vertex only once or multiple times. Closed walks are important in graph theory, as they can be used to study the properties of cycles and circuits in networks.

相关问题

报错Attempted to use a closed Session.

这个错误通常是因为在使用TensorFlow Session对象之前，已经关闭了Session。当Session关闭后，就无法再使用它来执行操作。

要解决这个问题，你可以检查以下几个方面：

1. 确保在Session对象被关闭之前，没有尝试再次使用它。
2. 确保在使用Session对象之前，已经正确地创建了它。你可以使用`tf.Session()`来创建一个新的Session对象。
3. 检查你的代码中是否存在多个Session对象被创建，而只有一个被关闭的情况。确保只创建一个Session对象，并且在不需要时正确地关闭它。

以下是一个示例代码，展示了如何正确地创建和使用一个TensorFlow Session对象：

import tensorflow as tf

# 创建一个会话
sess = tf.Session()

# 执行一些操作
a = tf.constant(1)
b = tf.constant(2)
c = tf.add(a, b)
result = sess.run(c)
print(result)

# 关闭会话
sess.close()

在这个示例中，我们首先创建了一个Session对象`sess`，然后执行了一些操作，并使用`sess.run()`来获取结果。最后，我们调用`sess.close()`来关闭Session。

如果你仍然遇到问题，请提供更多的代码细节，我将尽力帮助你解决问题。

ObjectDisposedException: Cannot write to a closed TextWriter.

This exception occurs when you try to write to a TextWriter object that has already been closed. Once a TextWriter object is closed, it cannot be used to write any further data.

To avoid this exception, check if the TextWriter object is closed before attempting to write to it. Alternatively, you can create a new TextWriter object and write to it instead.

Here is an example code snippet that shows how to check if a TextWriter object is closed:

TextWriter writer = new StreamWriter("file.txt");
// Write some data to the file
writer.Write("Hello World!");

// Close the writer
writer.Close();

// Attempt to write again
try
{
    writer.Write("This will throw an ObjectDisposedException");
}
catch (ObjectDisposedException ex)
{
    Console.WriteLine(ex.Message);
}

In the above example, the TextWriter object is closed before attempting to write to it again, which results in an ObjectDisposedException being thrown.