implement filtering on hyperparameters in hparams plugin

[drevicko]

It would be very useful to allow filtering on hyperparameters in the hparams UI. There doesn't seem to be such a functionality.

In my case, filtering on runs via a regex (similar to the standard plugins) would have similar effect (since my run names encode interesting hyperparameters) but this doesn't seem to be possible either.

Currently the only filter I can see is on the values of stored metrics.

I see two workarounds with the current plugin:

• store the interesting hyperparameters as metrics (even though they aren't strictly metrics)
• run multiple tb server instances, each selecting appropriate subfolders corresponding to combinations of interesting metrics, not particularly ideal..

tensorboard version 1.14.0

tensorflow version 2.0.0

[jerpint]

This would be a nice feature, at the very least to use the same regex that is implemented on the scalars page to filter the hparams page. It makes the scatter plot difficult to interpret without this support