id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
5795	The backend does not compute strong components of initial equations correctly with if initial() equations	Francesco Casella	Karim Adbdelhak	"Please have a look at the {{{PowerGrids.Examples.Tutorial.IslandOperation.TwoGeneratorsLocalInitialization}}} model, using {{{--tearingMethod=minimalTearing}}}. I get the nonlinear initial system 472 containing 65 unknowns, belonging to {{{GEN2}}}, {{{GRIDL2}}}, {{{LINE}}}, and {{{TGEN2}}}. According to the way the model is designed, the initial equations should result in two separate strong components, one involving unknowns from {{{GEN2}}}, the other one involving {{{GRIDL2}}}, {{{LINE}}}, and {{{TGEN2}}}. 

I manually went through all the equations using the debugger, and in fact I couldn't find any equation involving variables from both the subsets at the same time. So, unless I am missing something, I guess we not only have problems with nonlinear equation detection (see #5770), but also with Tarjan's algorithm and strong component detection. 

Please note some of these equations are found inside {{{if initial()}}} clauses, this could be relevant to find the root cause of the issue.

@Karim, can you please check ASAP?"	defect	closed	blocker	1.16.0	*unknown*		fixed		Andrea Bartolini adrien.guironnet@… Andreas Heuermann