[TASK][Plugin Merge] Merging `pysap-mri-online` to `pysap-mri`

[chaithyagr]

This issue tracks the merging of pysap-mri-online plugin developed by @paquiteau at here Steps to be done:

• [x] Generators: Return single trajectory of kspace data per iteration.
  • [x] Can it be batched? - Non-Cartesian?
• [X] Operators:
  • [X] Inherit from base classes in pysap-mri
  • Dont need prox op as it exists in modopt
• [x] Tests:
  • [X] Have tests in place for operators,
  • [x] integration test for complete reconstruction.
• [x] Optimizers:
  • [x] Basic gradient descent and acceleration operators: Move to Modopt! Have a chat with @sfarrens about [codes(https://github.com/paquiteau/pysap-mri-online/blob/master/online/optimizers/gradescent.py)
  • [x] For algorithms call, try to reduce redundancy and have the same function which creates online version of the algorithm.
    • [x] A lot of refactoring needed, @paquiteau to update on when can it be done (open a new issue if needed).
• [x] Reconstructors:
  • [x] Based on above refactoring, this must be added.

[paquiteau]

I don't plan on adding Non Cartesian Generator for now, It will probably requires some heavy changes in NonCartesianFFT/gpuNUFFT operators (update samples points and density compensation for instance), also, some extra algorithmic thinking (like the one of ColumnFFT) needs to be found to make it worth.

[paquiteau]

The ModOpt Integration of optimizer is tracked here: https://github.com/CEA-COSMIC/ModOpt/issues/194. The pull request associated is here: https://github.com/CEA-COSMIC/ModOpt/pull/195

[chaithyagr]

@paquiteau can we close this?

[paquiteau]

Yes ! All PR have been merged in their corresponding repos.