TensorFlow，TensorBoard:未找到标量数据

import tensorflow as tf

# 创建一个文件写入器
summary_writer = tf.summary.create_file_writer('logs')

with summary_writer.as_default():
    for step in range(100):
        # 记录标量数据
        tf.summary.scalar('loss', loss_value, step=step)
        summary_writer.flush()

tensorboard --logdir logs

ls logs

tensorboard --logdir logs --port 6006

import tensorflow as tf
import numpy as np

# 创建一个文件写入器
summary_writer = tf.summary.create_file_writer('logs')

for step in range(100):
    # 生成一些示例数据
    loss_value = np.random.rand()
    
    with summary_writer.as_default():
        # 记录标量数据
        tf.summary.scalar('loss', loss_value, step=step)
        summary_writer.flush()

# 启动 TensorBoard
# 在终端中运行以下命令：
# tensorboard --logdir logs --port 6006