id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
5817	Usage of three-phase Aron sensor got problematic last December 2019	massimo ceraolo	Karim Adbdelhak	"Consider attached models InvSW and InvSWaron. They differ only for an Aron sensor; however, the first model runs correctly with recent builds, while the second one causes run-time messages (below) and fails.

Since both worked well last summer, I tried to understand when this issue was introduced.
I checked that
- with OM 1.15.0-dev 35 (6th of last December) both models work well
- with PM 1.16.0-dev-63 (should have been generated just before 15th of December) only InvSW runs correctly.

Error message (first rows):

{{{
The default linear solver fails, the fallback solver with total pivoting is started at time 0.000000. That might raise performance issues, for more information use -lv LOG_LS.
Matrix singular!
Failed to solve linear system of equations (no. 269) at time 0.000000, system is singular for U[2, 2].
The default linear solver fails, the fallback solver with total pivoting is started at time 0.000000. That might raise performance issues, for more information use -lv LOG_LS.
Matrix singular!
Failed to solve linear system of equations (no. 269) at time 0.000000, system is singular for U[2, 2].
The default linear solver fails, the fallback solver with total pivoting is started at time 0.000000. That might raise performance issues, for more information use -lv LOG_LS.
Matrix singular!
Failed to solve linear system of equations (no. 269) at time 0.000000, system is singular for U[2, 2].
The default linear solver fails, the fallback solver with total pivoting is started at time 0.000000. That might raise performance issues, for more information use -lv LOG_LS.
Failed to solve linear system of equations (no. 48) at time 0.000000, system is singular for U[2, 2].
Matrix singular!
Failed to solve linear system of equations (no. 269) at time 0.000000, system is singular for U[2, 2].
The default linear solver fails, the fallback solver with total pivoting is started at time 0.000000. That might raise performance issues, for more information use -lv LOG_LS.
Matrix singular!
Failed to solve linear system of equations (no. 269) at time 0.000000, system is singular for U[2, 2].
The default linear solver fails, the fallback solver with total pivoting is started at time 0.000000. That might raise performance issues, for more information use -lv LOG_LS.
Matrix singular!
under-determined linear system not solvable!
Error solving linear system of equations (no. 269) at time 0.000000.
Solving linear system 269 fails at time 1.36931e-009. For more information use -lv LOG_LS.
The default linear solver fails, the fallback solver with total pivoting is started at time 0.000000. That might raise performance issues, for more information use -lv LOG_LS.
Matrix singular!
Failed to solve linear system of equations (no. 269) at time 0.000000, system is singular for U[2, 2].
The default linear solver fails, the fallback solver with total pivoting is started at time 0.000000. That might raise performance issues, for more information use -lv LOG_LS.
Matrix singular!
The initialization finished successfully without homotopy method.
Failed to solve linear system of equations (no. 269) at time 0.000000, system is singular for U[2, 2].
}}}
"	defect	closed	blocker	1.18.0	Backend		fixed