Tobias Ribizel

### Describe the bug The assessment view highlights changed lines in green, but those highlights are partially incorrect in most files I examined. ### To Reproduce Examine the repository and...

Add minimum iteration stopping criterion wrapper

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Closes #1879

Simpler stopping criterion interface

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This replaces typed stopping criteria like ```cpp .with_criteria(gko::stop::ResidualNorm::build().with_baseline(gko::stop::mode::absolute).with_reduction_factor(1e-5)) ``` by the simpler ```cpp .with_criteria(gko::stop::abs_residual_norm(1e-5)) ```

This is showcasing a prototype interface design for reusable LinOpFactories both for low-level functionality (Factorization, Reordered) and composite LinOps (Direct, Reordered). It is based on the ReuseData hierarchy, which is...

Remove `AbstractFactory` base class

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The `AbstractFactory` base class doesn't really provide any useful functionality, since all of the important things are happening inside the `LinOpFactory::generate` or `Criterion::generate` functions. `AbstractFactory::generate` doesn't even call the loggers...