Tensorboard在TF2.0中显示没有keras.fit或estimator的标量

Question

我已阅读TF 2.0教程：Using TensorBoard with other methods 然后我写了这个简单的代码，但似乎不起作用：

import tensorflow as tf

train_loss = tf.keras.metrics.Mean('train_loss', dtype=tf.float32)
test_loss = tf.keras.metrics.Mean('test_loss', dtype=tf.float32)

train_summary_writer = tf.summary.create_file_writer('logs/tr')
test_summary_writer = tf.summary.create_file_writer('logs/ts')

for ep in range(1000):
    train_loss(1*ep) # here I just want to display 1*ep...
    test_loss(2*ep) 
    tf.summary.scalar('trloss', train_loss.result(), step=ep)
    tf.summary.scalar('tsloss', test_loss.result(), step=ep)

%tensorboard --logdir logs

我得到了（在浏览器中）：

No scalar data was found.
Probable causes:

You haven’t written any scalar data to your event files.
TensorBoard can’t find your event files.

我错过了什么吗？

Answer 1

我自己回答：

with train_summary_writer.as_default():
    tf.summary.scalar('trloss', train_loss.result(), step=ep)
with test_summary_writer.as_default():
    tf.summary.scalar('tsloss', test_loss.result(), step=ep)

有效！但是，我找不到与此相关的任何文档。