[ONNX FE] Add SoftmaxCrossEntropyLoss operator to ONNX Frontend

[AJThePro99]

This pull request implements the SoftmaxCrossEntropyLoss operation for the ONNX frontend in OpenVINO, supporting opset 12 and opset 13. It includes new header and source files to define and implement the operation.

Ticket #20547

New operation implementation:

• src/frontends/onnx/frontend/src/op/softmax_cross_entropy_loss.hpp: Added the header file defining the SoftmaxCrossEntropyLoss operation for opset 12 and opset 13.
• src/frontends/onnx/frontend/src/op/softmax_crossentropy_loss.cpp: Added the source file implementing the SoftmaxCrossEntropyLoss operation, including the shared helper function impl_softmax_cross_entropy to compute the loss.

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TODO

• 1. Create softmax_cross_entropy_loss.cpp & softmax_cross_entropy_loss.hpp
• 2. Add implementation of SoftMaxCrossEntropyLoss for opset_12 & opset_13
• 3. Register the function using ONNX_OP() macro
• Creating test models within ONNX Models directory
• Added test cases covering all use cases here
• Check Python xfailed tests for added functionality
• Final code formatting to adhere to OpenVINO codebase standards

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P.S.: I'm very new to contributing to large codebases, and I want to know if my work meets the standards and most of all, is what's expected!

As a new contributor, I would really appreciate your guidance on the following:

1. Does the implementation meet OpenVINO standards?
2. Are there additional edge cases or test scenarios I should include? (Excluding TODOs)
3. How can I improve code readability, efficiency, or maintainability?

[AJThePro99]

Hi @gkrivor
I’ve created a draft pull request for the implementation of SoftmaxCrossEntropyLoss. Since I’m new to contributing to OpenVINO, I’d appreciate it if you could take a look and let me know if I’m on the right track. Let me know if there are any changes or additional requirements I should address. Thanks for your time!

[rkazants]

I think weights are also needed according to the spec. Please check.

[AJThePro99]

Hello!
I'd like to know if there exists a way to build the components of only the onnx frontend instead of the entire project src/frontends/onnx

It does have a CMakeLists.txt file, so I'm wondering if I could save time by doing that.
Or, does it not work that way?