id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
5316	Error: The given system is mixed-determined.   [index > 3] is very confusing	Francesco Casella	Karim Adbdelhak	"Sometimes the back-end stops with this error:
{{{
Error: The given system is mixed-determined.   [index > 3]
Please checkout the option ""--maxMixedDeterminedIndex"".
Error: No system for the symbolic initialization was generated
}}}
see, e.g., [https://libraries.openmodelica.org/branches/newInst/Modelica_trunk/files/Modelica_trunk_Modelica.Electrical.Analog.Examples.ResonanceCircuits.err Modelica.Electrical.Analog.Examples.ResonanceCircuits].

The message is quite obscure, for three main reasons:
- it doesn't make it explicit that the issue is only with the ''initialization problem''. I know it pops up while the backend is processing the initialization problem, but it's not obvious anyway.
- it refers to the term ''index'' which has a well-defined ''completely different'' meaning in the context of DAE modelling, and is very, very confusing.
- it doesn't really help understanding what to do, but mostly just scares off users.

I myself only recently understood that this somewhat means the initialization problem is under- and over-determined at the same time (though I'm still not 100% sure what this message really means). If that is the case, I would write that explicitly.

I would strongly suggest to improve the situation by changing the message, so that people do not fall into one of the three semantic traps I listed above. I'm available to discuss the details of the message in this ticket."	defect	closed	blocker	1.14.0	Backend		fixed