Graphviz fix

[GNroy]

What does this PR do ?

• Fixes graphviz cropped plots for notebooks
• Fixes duplicated Megatron-LM installation
• Fixes k2 library for compatibility with latest PyTorch

Collection: [ASR]

Changelog

• Now graphviz is built and installed from sources.

Usage

• You can potentially add a usage example below

# Add a code snippet demonstrating how to use this 

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• New Feature
• Bugfix
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Additional Information

• Related to # (issue)

[artbataev]

Thanks for these fixes! I tested Docker build - everything is fine.

[GNroy]

Hi @titu1994, I've addressed your comments.
graphviz is for WFST visualization (k2, pynini, ...)
Its binary does not display plots correctly in notebooks.
I've added the correct installation (implying build from source).

[artbataev]

LGTM!

[titu1994]

Needs discussing about license (non standard), necessity (why is a graph visualization library a required dependency for K2 ??) And whether it's realistic to bloat the apt get section wth so many libraries.

[GNroy]

The licence is Eclipse Public License - v 1.0: https://gitlab.com/graphviz/graphviz/-/blob/main/epl-v10.txt (weak copyleft).

[github-actions]

This PR is stale because it has been open for 14 days with no activity. Remove stale label or comment or update or this will be closed in 7 days.

[github-actions]

This PR was closed because it has been inactive for 7 days since being marked as stale.

[GNroy]

Hi all!
I just re-opened this PR and addressed comments of @titu1994.
The legal has approved general use of graphviz (the container use included).

[titu1994]

It's not been discussed yet - why is a graph visualization library being installed in the container ?

[GNroy]

why is a graph visualization library being installed in the container?

Simply for convenient prototyping. I always work inside NeMo containers (maybe I'm not the only one in that) and I'd like to have graphviz already installed rather than having to manually install it every time I run a new image.

[titu1994]

Thank you for all the clarification and legal review. Looks good to merge