Tensorboard multiple graphs are shown with only one program

Question

When running an mnist classification program to view in tensorboard it shows multiple graphs even though there is only meant to be one. I get the error message:

and the graphs look like:

Answer 1

This looks as if it is due to the presence of multiple tensorboard files within the same directory. Presumably, you have run the training many times, each time passing the same logdir argument to the tf.summary.FileWriter constructor. To solve the problem, delete all of the tensorboard files within the logdir you have been writing to and run training again. You should then see only one trace.

If you wish to be able to view multiple runs without any issues, save each run in a different subdirectory within a summaries parent directory, e.g. summaries/run1, summaries/run2 etc. Running tensorboard with logdir=summaries will then display the runs nicely together, as detailed at How do display different runs in TensorBoard? and https://github.com/tensorflow/tensorflow/issues/1548 .

Edit: Also, as highlighted by @Engineero in their comment, using the relative or wall viewing options on the tensorboard browser page will “chain together” runs within the logdir into a time series.