Tensorflow (1.4.1) Tensorboard visualization plot

问题:

I created a few summary ops throughout my graph like so:

tf.summary.scalar('cross_entropy', cross_entropy)
tf.summary.scalar('accuracy', accuracy)

and of course merged and got a writer:

sess = tf.InteractiveSession()
summaries = tf.summary.merge_all()
train_writer = tf.summary.FileWriter(TENSORBOARD_TRAINING_DIR, sess.graph)
tf.global_variables_initializer().run()

and I write these in each training iteration:

summary, acc = sess.run([summaries, accuracy], feed_dict={...})
train_writer.add_summary(summary, i)

when I load the tensorboard, I get some weird results:

this is weird for a couple reasons:

1. Y-axis on cross_entropy graph doesn't have increasing (or different) tick marks
2. Line plots appear to fold back on itself or go back in time

I did check - there are a few previous event files in my training summaries folder:

$ ls /tmp/tv_train/
events.out.tfevents.1517210066.xxxxxxx.local    
events.out.tfevents.1517210097.xxxxxxx.local    
...
events.out.tfevents.1517210392.xxxxxxx.local

I think I must have restarted the train loop at some point, causing there to be multiple summaries logged at (0, 1, etc) indices.

How can I append to old training logs? Can I point my writer to a specific tfevents file to "start back where I left off"?

回答1:

You can't (easily) reopen and "append" to an existing events file, but that's not necessary. Tensorboard will display sequential event files just fine, as long as the step value in the records is consistent. When you save a summary, you specify a step value, which indicates at which point on the x axis the summary should be plotted.

The graph goes "back in time" because at every new run you restart the step counter from 0. To have it consistent in multiple runs, you should define a global_step variable that is saved to the checkpoint when you save the network. This way, when you restore the network in the next training run, your global step will pick up from where it left and your graphs will not look weird anymore.