Columnar analysis and on-the-fly analysis corrections at ATLAS

Current analysis at ATLAS always involves a step of producing an analysis-specific n-tuple that incorporates the final step of calibrations as well as systematic variations. The goal for Run 4 is to make these analysis-specific corrections fast enough that they can be applied "on-the-fly" without the need for an intermediate n-tuple. The main complications for this are that some of these corrections have very complex implementations, and that a wide range of environments needs to be supported. An early prototype will be presented.