fix torch frontend blas_and_lapack_ops cholesky

[Daniel4078]

PR Description

Related Issue

Closes #28766

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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[Daniel4078]

locally, for the 5 frontend tests of test_torch_cholesky, only one of paddle fails with RuntimeError('(NotFound) The kernel with key (CPU, Undefined(AnyLayout), bfloat16) of kernel cholesky is not registe...cond.end() && kernel_key.backend() == Backend::CPU:1 == true:1.] (at /paddle/paddle/phi/core/kernel_factory.cc:262)\n')

[Daniel4078]

Now it seems like the target test_torch_cholesky is no longer failing according to the github pipeline

[Sam-Armstrong]

Thanks for the contribution @Daniel4078!

I've just had a look at the failing test for torch.linalg.cholesky, and it seems the problem is actually with the test itself. I was able to fix it for all backends by changing this line:

x = np.matmul(x.T, x) + np.identity(x.shape[0])

to this:

x = np.matmul(np.conjugate(x.T), x) + np.identity(x.shape[0], dtype=dtype[0])

Would you be able to make this change, and see if it also works for the version in blas_and_lapack_ops? (you can remove all these current changes you made) Thanks!

[Daniel4078]

@Sam-Armstrong Thank you! I have checked, your changes also work in this blas_and_lapack_ops version. And I think this PR should be ready to be merged. Just in case, have you already pushed the fix to the linalg version or should I include it in this PR?

[Sam-Armstrong]

Looks good to me. Thanks a lot @Daniel4078!