Models may have zero-crossing events at the simulation start time that are picked up at a small time past startup by traditional solvers that detect crossings rather than predicting them like QSS. Ideally, QSS should either detect such events and reject such models or accept and process those events.
Models may have zero-crossing events at the simulation start time that are picked up at a small time past startup by traditional solvers that detect crossings rather than predicting them like QSS. Ideally, QSS should either detect such events and reject such models or accept and process those events.
It is not clear whether should disallow models with such events but in some cases it is possible to eliminate them, as in https://github.com/lbl-srg/modelica-buildings/pull/2571.