id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
5452	Numerical issues due to missing index reduction	Francesco Casella	Karim Adbdelhak	"Please consider the results of the simulation of [https://libraries.openmodelica.org/branches/newInst/Modelica_3.2.3/files/Modelica_3.2.3_Modelica.Electrical.Machines.Examples.AsynchronousInductionMachines.AIMC_InverterDrive.sim Modelica.Electrical.Machines.Examples.AsynchronousInductionMachines.AIMC_InverterDrive].

The initialization terminates correctly, but when the simulation starts, the step length is reduced down to 7e-15, and then the simulation fails. It looks like the DAE system is somewhat singular (e.g., locally index 2), in the sense that all state derivatives cannot be uniquely computed at the beginning of the state-space simulator. The same behviour takes place with the old front-end.

The exact reason of this singularity is yet unknown, it should be analyzed and then fixed."	defect	reopened	blocker	1.19.0	Backend				Karim Adbdelhak Lennart Ochel Volker Waurich dr.christian.kral@… a.haumer@…