Plot multiple 2D images as cards in the same tag

[MattTheCuber]

Fixes #7724.

Description

This will change the plot_2d_or_3d_image function to plot multiple 2D images under the same tag as multiple cards rather than each image as a separate tag in TensorBoard. See #7724 for more information and examples at the bottom.

This might not be the optimal way to solve this issue, let me know if you have other ideas.

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).
• Breaking change (fix or new feature that would cause existing functionality to change).
• New tests added to cover the changes.
• Integration tests passed locally by running ./runtests.sh -f -u --net --coverage.
• Quick tests passed locally by running ./runtests.sh --quick --unittests --disttests.
• In-line docstrings updated.
• Documentation updated, tested make html command in the docs/ folder.

[atbenmurray]

Hi @MattTheCuber, taking a look

[atbenmurray]

Let's add a flag to control this behaviour. I'm also having a look at the tests to see if there are tests for this function that need augmenting

[atbenmurray]

In order to preserve existing behaviour for users, this change should be controlled by a flag passed in as an argument to plot_2d_or_3d_image. with the default being the existing behaviour.

[MattTheCuber]

The current behavior is inconsistent between different image types. Currently, multiple 3D images are plotted in the same tag while multiple 2D images are plotted in different tags. I would think consistency would be preferred over preserving the current behavior? Also, the flag should probably control all image sizes and not just 2D?

[atbenmurray]

Hi @MattTheCuber,
I agree that it is a little inconsistent in its current form, but preserving current behaviour is always preferred and we always like to warn users in advance if default behaviour is changing. If we were to change it without giving users the ability to control the behaviour it makes comparisons between runs done before and after the change very hard.

We would instead do the following:

1. introduce the flag to switch between current behaviour and the suggested change
2. schedule a change to the default setting for that flag for a future release and add suitable documentation so that users have time to change scripts if they need to do so

As for the 2d vs 3d discrepancy, I think there might be a broader question as to whether this method is sufficiently flexible and the best way of addressing it. We have a core development meeting today; I'll raise the issue and see what folks have to say, then come back to you.

[KumoLiu]

Hi @MattTheCuber, we can simply add a flag for this multi-channel 2d image plt. Thanks.

[atbenmurray]

@KumoLiu I was thinking that if we looked a bit more of a refactor we might want to give the caller more flexibility in how their data is displayed in tensorboard:

• 2d data
  • image
• 3d data
  • image ((rgb)HW)
  • image with '_' tag (CHW)
  • image with '/' tag (CHW)
  • video (DHW) / (THW)
  • animated_gif (DHW) / (THW)
• 4d data
  • video (rgb(DHW)) / (rgb(THW))
  • animated_gif

[MattTheCuber]

I agree, refactoring this would be nice. As I said previously, the current behavior is quite disjoint.