>>> model = tf.keras.models.Sequential([ ... tf.keras.layers.Dense(64, activation='relu'), ... tf.keras.layers.Dense(10, activation='softmax') ... ]) >>> tensorboard_callback = tf.keras.callbacks.TensorBoard(log_dir="./logs") >>> model.fit(x_train, y_train, epochs=10, callbacks=[tensorboard_callback]) Traceback (most recent call last): File "<stdin>", line 1, in <module> NameError: name 'x_train' is not defined

这个错误提示是因为在运行这段代码之前没有定义变量 x_train。x_train 和 y_train 应该是训练模型所需的输入数据和对应的标签。你需要先定义这两个变量并将它们传递给 model.fit() 方法。例如：

import tensorflow as tf

# 定义 x_train 和 y_train
x_train = ...
y_train = ...

model = tf.keras.models.Sequential([
  tf.keras.layers.Dense(64, activation='relu'),
  tf.keras.layers.Dense(10, activation='softmax')
])

tensorboard_callback = tf.keras.callbacks.TensorBoard(log_dir="./logs")
model.fit(x_train, y_train, epochs=10, callbacks=[tensorboard_callback])

你需要将 `...` 替换为你自己的数据和标签。