Replace indptr with sparse and dense grouped index vector

[mgovers]

Replace indptr with SparseIdxVector

[TonyXiang8787]

@mgovers this PR needs more attention. Do not blindly change every indptr to Sparse mapping. Some of them should actually be dense mapping. This involves the physical knowledge to see what makes sense for a typical power grid.

[mgovers]

@mgovers this PR needs more attention. Do not blindly change every indptr to Sparse mapping. Some of them should actually be dense mapping. This involves the physical knowledge to see what makes sense for a typical power grid.

Yes i agree. But i need your (or someone else's) input for that. Hence also my comment on the common data type.

• I made sure to only ever use auto, so changing the classes is almost trivial. The from_sparse tag ensures that no constructor input needs to be changed for that change.
• Changing the input data type is a littlebit more tricky, because it requires modifying e.g test data. But i strongly feel that this PR should only change classes, not test data, to separate dangerous refactorings (it's easy to make a mistake)

[mgovers]

@mgovers this PR needs more attention. Do not blindly change every indptr to Sparse mapping. Some of them should actually be dense mapping. This involves the physical knowledge to see what makes sense for a typical power grid.

Yes i agree. But i need your (or someone else's) input for that. Hence also my comment on the common data type.

* I made sure to only ever use `auto`, so changing the classes is almost trivial. The `from_sparse` tag ensures that no constructor input needs to be changed for that change.

* Changing the input data type is a little bit more tricky, because it requires modifying e.g test data. But i strongly feel that this PR should only change classes, not test data, to separate dangerous refactorings (it's easy to make a mistake)

We agreed during standup that this is actually how we should approach this PR to prevent too many changes from happening in one go

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
1 Code Smell

100.0% Coverage
2.0% Duplication