# Frequently Asked Questions (without Answers)

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Feel free to add any Ginkgo related question here
:::

## Questions from the Tutorial

- s.7.1. reorder solver apply to show linear system, rename/reorder vectors
  - how is S stored? as A^-1?
  - use solver as preconditioner?
  - combination: are the entries of C calculated?
- s.12 duplicate entries?
  - difference between device_matrix_data and matrix_assembly_data
  - meaning of sum_duplicates function?
- s.15.4 possible to combine criterion 1 and 2?
  - what is residual norm criteria?
- left or right preconditioning?
- why output parameters (e.g. apply)?
- why is the `.on` required for the factory?
- cheatsheet???