Estimators should not try to modify X and y inplace in order to handle readonly memory maps #5481
Description
PR #4807 reveals a variety of estimators that fails on memory mapped input, once we allow check_array to process a memory map without copying its content in memory.
Estimators failing on read only memory maps :
- the whole PLS family
- Factor analysis
- Incremental PCA
- NuSVC
Transformers :
- KernelCenterer
- MaxAbsScaler
- MinAbsScaler
- RobustScaler
- StandardScaler
Most of these should be easy to fix (e.g X -= X.mean should be replaced etc.)