fix: bug in elementwise base for static inputs

[zewenli98]

Description

Fixes #2774 #2726

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the style guidelines of this project (You can use the linters)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas and hacks
• I have made corresponding changes to the documentation
• I have added tests to verify my fix or my feature
• New and existing unit tests pass locally with my changes
• I have added the relevant labels to my PR in so that relevant reviewers are notified

[chohk88]

This looks good to me. It seems like it could resolve the CI/CD issues mentioned in 2726

[chohk88]

It seems that we've encountered an accuracy issue in the CI/CD test, which wasn't quite what we expected. Could this be the error you mentioned occurring in TRT-10?

[zewenli98]

Could this be the error you mentioned occurring in TRT-10?

@chohk88 Yes that's it! The issue here is that the original broadcast() function in fx/conterver_utils.py only broadcasts two ITensors to the same number of dimensions (ranks) by prepending 1s, which results in the error in the following ctx.net.add_elementwise(). For fixing this, I wrote another similar broadcast function, called broadcast_to_same_shape that can broadcast two ITensors to the exactly same shape.

For example, we have original ITensors: lhs_val.shape: (2, 3) rhs_val.shape: (2, 2, 1, 3)

• If calling fx/converter_utils.broadcast, lhs_val.shape: (1, 1, 2, 3) lhs_val.shape: (2, 2, 1, 3).
• If calling broadcast_to_same_shape, lhs_val.shape: (2, 2, 2, 3) lhs_val.shape: (2, 2, 2, 3).

I think this fix should also work for #2726

[chohk88]

This looks good to me.

[zewenli98]

@peri044 Is this PR needed to be cherry-picked to release/2.3?