fix: Reformatted gather to use torch backend for its backend-specific implementation. Updated docstrings.

[Kacper-W-Kozdon]

PR Description

fix #26498 Edited gather to use torch methods in backend. Updated docstrings.

Related Issue

Closes #26498

Checklist

• [⏩] Did you add a function?
• [⏩] Did you add the tests?
• [❌] Did you run your tests and are your tests passing?
• [✅] Did pre-commit not fail on any check?
• [✅] Did you follow the steps we provided?

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PR Compliance Checks Passed!

[Kacper-W-Kozdon]

Reformatting Task Checklist

IMPORTANT NOTICE 🚨:

The Ivy Docs represent the ground truth for the task descriptions and this checklist should only be used as a supplementary item to aid with the review process.

LEGEND 🗺:

• ❌ : Check item is not completed.
• ✅ : Check item is ready for review.
• 🆘 : Stuck/Doubting implementation (PR author should add comments explaining why).
• ⏩ : Check is not applicable to function (skip).
• 🆗 : Check item is already implemented and does not require any edits.

CHECKS 📑:

1. • ✅: Remove all lambda and direct bindings for the backend functions in:
     • ✅: ivy/functional/backends/jax/Reformatting_general.py.
     • ✅: ivy/functional/backends/numpy/Reformatting_general.py.
     • ✅: ivy/functional/backends/tensorflow/Reformatting_general.py.
     • ✅: ivy/functional/backends/torch/Reformatting_general.py.
2. • ❌: Implement the following if they don't exist:
     1. • ❌: The ivy.Array instance method in ivy/data_classes/array/Reformatting_general.py.
     2. • ❌: The ivy.Array special method in ivy/data_classes/array/array.py.
     3. • ❌: The ivy.Array reverse special method in ivy/data_classes/array/array.py.
     4. • ❌: The ivy.Container static method in ivy/data_classes/container/Reformatting_general.py.
     5. • ❌: The ivy.Container instance method in ivy/data_classes/container/Reformatting_general.py.
     6. • ❌: The ivy.Container special method in ivy/data_classes/container/container.py.
     7. • ❌: The ivy.Container reverse special method in ivy/data_classes/container/container.py.
3. • ❌: Make sure that the aforementioned methods are added into the correct category-specific parent class, such as ivy.ArrayWithElementwise, ivy.ContainerWithManipulation etc.
4. • 🆗: Correct all of the Function Arguments and the type hints for every function and its relevant methods, including those you did not implement yourself.
5. • ❌: Add the correct Docstrings to every function and its relevant methods, including those you did not implement yourself. The following should be added:
     1. • ❌: The function's Array API standard description in ivy/functional/Reformatting_general.py. If the function is not part of the Array API standard then a description of similar style should be added to the same file.
          The following modifications should be made to the description:
          • ✅: Remove type definitions in the Parameters and Returns sections.
          • 🆗: Add out to the Parameters section if function accepts an out argument.
          • 🆗: Replace out with ret in the Returns section.
     2. • ❌: Reference to docstring for ivy.function_name (5.a) for the function description and modified Parameters and Returns sections as described in the docs in:
          • ❌: ivy/array/Reformatting_general.py.
          • ❌: ivy/container/Reformatting_general.py (in the static and instance method versions).
          • ❌: ivy/array/array.py if the function has a special method ( like __function_name__ ).
          • ❌: ivy/array/array.py if the function has a reverse special method ( like __rfunction_name__ ).
          • ❌: ivy/container/container.py if the function has a special method ( like __function_name__ ).
          • ❌: ivy/container/container.py if the function has a reverse special method ( like __rfunction_name__ ).

6. • 🆗: Add thorough Docstring Examples for every function and its relevant methods and ensure they pass the docstring tests.

     Functional Examples in ivy/functional/Reformatting_general.py.

     1. • ❌: Cover all possible variants for each of the arguments independently (not combinatorily).
     2. • ❌: Vary the values and input shapes considerably between examples.
     3. • 🆗: Start out simple and get more complex with each example.
     4. • 🆗: Show an example with:
          • 🆗: out unused.
          • 🆗: out used to update a new array y.
          • 🆗: out used to inplace update the input array x (if x has the same dtype and shape as the return).
     5. • ❌: If broadcasting is relevant for the function, then show examples which highlight this.

     Nestable Function Examples in ivy/functional/Reformatting_general.py.
     Only if the function supports nestable operations.

     6. • 🆗: Add an example that passes in an ivy.Container instance in place of one of the arguments.
     7. • 🆗: Add an example passes in ivy.Container instances for multiple arguments.

     Container Static Method Examples in ivy/container/Reformatting_general.py.

     8. • ❌: The example from point (6.f) should be replicated, but added to the ivy.Container static method docstring in with ivy.<func_name> replaced with ivy.Container.static_<func_name> in the example.
     9. • ❌: The example from point (6.g) should be replicated, but added to the ivy.Container static method docstring, with ivy.<func_name> replaced with ivy.Container.static_<func_name> in the example.

     Array Instance Method Example in ivy/array/Reformatting_general.py.

     10. • ❌: Call this instance method of the ivy.Array class.

     Container Instance Method Example in ivy/container/Reformatting_general.py.

     11. • ❌: Call this instance method of the ivy.Container class.

     Array Operator Examples in ivy/array/array.py.

     12. • ⏩: Call the operator on two ivy.Array instances.
     13. • ⏩: Call the operator with an ivy.Array instance on the left and ivy.Container on the right.

     Array Reverse Operator Example in ivy/array/array.py.

     14. • ⏩: Call the operator with a Number on the left and an ivy.Array instance on the right.

     Container Operator Examples in ivy/container/container.py.

     15. • ⏩: Call the operator on two ivy.Container instances containing Number instances at the leaves.
     16. • ⏩: Call the operator on two ivy.Container instances containing ivy.Array instances at the leaves.
     17. • ⏩: Call the operator with an ivy.Container instance on the left and ivy.Array on the right.

     Container Reverse Operator Example in ivy/container/container.py.

     18. • ⏩: Following example in the ivy.Container.__radd__ docstring, with the operator called with a Number on the left and an ivy.Container instance on the right.

     Tests

     19. • ❌: Docstring examples tests passing.
     20. • ✅: Lint checks passing.

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[github-actions]

Thank you for this PR, here is the CI results:

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This pull request does not result in any additional test failures. Congratulations!

[Sam-Armstrong]

@Kacper-W-Kozdon I see you have a separate PR for this here #27071, so I'm assuming this can be closed?

[Kacper-W-Kozdon]

@Kacper-W-Kozdon I see you have a separate PR for this here #27071, so I'm assuming this can be closed?

Yes, this one can be closed, sorry for the confusion.