[DFT] Add more warning flags

[Rbiessy]

Description

This PR builds on #259.

Fix warnings when compiling the DFT domain with some warning flags:
-Wall -Wextra -Wshadow -Wconversion -Wpedantic.
The same warnings can be added to more domains if desired.

As part of fixes the warnings this also splits the DFT descriptor tests
as the device was not needed for some of them.

Checklist

All Submissions

• Do all unit tests pass locally? Attach a log.
• Have you formatted the code using clang-format?

New interfaces

• Have you provided motivation for adding a new feature as part of RFC and
  it was accepted? # (RFC)
• What version of oneAPI spec the interface is targeted?
• Complete New features checklist

New features

• Have you provided motivation for adding a new feature?
• Have you added relevant tests?

Bug fixes

• Have you added relevant regression tests?
• Have you included information on how to reproduce the issue (either in a
  GitHub issue or in this PR)?

[Rbiessy]

Tests log: tests_log.txt
Specific DFT test logs with the descriptor tests split: test_dft_log.txt
Note the lapack failures are not related to these changes and the DFT example is expected to fail with the CPU backend with #259 as it is not supported yet.

[FMarno]

Looks pretty good.

[Rbiessy]

I have reworded the first commit description.
Logs after re-running the descriptor tests: test_dft_descriptor_log.txt

[lhuot]

Tests log: tests_log.txt Specific DFT test logs with the descriptor tests split: test_dft_log.txt Note the lapack failures are not related to these changes and the DFT example is expected to fail with the CPU backend with #259 as it is not supported yet.

I see 5952 - dft/EXAMPLE/RT/real_fwd_usm/cpu (Failed)
in the test log. I thought we disabled the DFT test on CPU. Why is this still running?

[lhuot]

I think it would be good to be consistent across all domains for the warning flag used. It can be done in separate PR though.
@mkrainiuk @aelizaro @mmeterel do you agree with the general idea of using those warning flag?

[Rbiessy]

Tests log: tests_log.txt Specific DFT test logs with the descriptor tests split: test_dft_log.txt Note the lapack failures are not related to these changes and the DFT example is expected to fail with the CPU backend with #259 as it is not supported yet.

I see 5952 - dft/EXAMPLE/RT/real_fwd_usm/cpu (Failed) in the test log. I thought we disabled the DFT test on CPU. Why is this still running?

The log is older, we only recently disabled the DFT tests for the CPU backend. It's not a risk here anyway.

[mkrainiuk]

I think it would be good to be consistent across all domains for the warning flag used. It can be done in separate PR though. @mkrainiuk @aelizaro @mmeterel do you agree with the general idea of using those warning flag?

I think it's a good practice to build without any warnings, so I agree with this idea. And we can add this flags to other domains after fixing all problems if we have any.

[lhuot]

@Rbiessy please let me know if you'd still like to make some changes here or if I can merge this PR. Thanks!

[Rbiessy]

@Rbiessy please let me know if you'd still like to make some changes here or if I can merge this PR. Thanks!

Yes I am happy to see this merged once all the conversations are resolved, thanks!

Note that we should make sure future PRs in the DFT domain don't create warnings.