id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
4874	Lots of equations coming out of nowhere in the NF	Francesco Casella	Per Östlund	"Please consider the model [https://libraries.openmodelica.org/branches/newInst/Modelica_3.2.2/files/Modelica_3.2.2_Modelica.Electrical.Spice3.Examples.CascodeCircuit.err Modelica.Electrical.Spice3.Examples.CascodeCircuit]. After ""Trasformations before backend"" the NF reports:
{{{
Error: Too many equations, over-determined system. The model has 298 equation(s) and 68 variable(s).
}}}

I flattened the model in OMEdit and the result definitely has around 70 equations, not around 300:
{{{
  J2.D.v = J1.S.v;
  UDD.n.v = ground.p.v;
  UDD.n.v = U0.n.v;
  UDD.n.v = v_sin.n.v;
  UDD.n.v = J2.S.v;
  v_sin.p.v = J2.G.v;
  U0.p.v = J1.G.v;
  J1.D.v = RC.p.v;
  UDD.p.v = RC.n.v;
  RC.p.i + J1.D.i = 0.0;
  J2.D.i + J1.S.i = 0.0;
  v_sin.n.i + U0.n.i + UDD.n.i + ground.p.i + J2.S.i = 0.0;
  UDD.p.i + RC.n.i = 0.0;
  U0.p.i + J1.G.i = 0.0;
  v_sin.p.i + J2.G.i = 0.0;
  J1.p = Modelica.Electrical.Spice3.Internal.Jfet.jfetRenameParameters(J1.modelcard);
  J1.m = Modelica.Electrical.Spice3.Internal.Fet.fetRenameParametersDev(J1.AREA, J1.OFF, J1.IC_VDS, J1.IC_VGS, J1.UIC, J1.TEMP);
  J1.p1 = Modelica.Electrical.Spice3.Internal.Jfet.jfetInitEquations(J1.m, J1.p);
  J1.p2 = Modelica.Electrical.Spice3.Internal.Jfet.jfetModelLineInitEquations(J1.p1);
  J1.m1 = Modelica.Electrical.Spice3.Internal.Jfet.jfetCalcTempDependencies(J1.m, J1.p2);
  J1.cc = Modelica.Electrical.Spice3.Internal.Jfet.jfetNoBypassCode(J1.m1, J1.p2, J1.m_type, false, {J1.G.v, J1.Dinternal, J1.Sinternal});
  J1.vGD = J1.G.v - J1.Dinternal;
  J1.vGS = J1.G.v - J1.Sinternal;
  J1.ird * J1.p2.m_drainResist = J1.D.v - J1.Dinternal;
  J1.irs * J1.p2.m_sourceResist = J1.S.v - J1.Sinternal;
  J1.icGD = J1.cc.cGD * der(J1.vGD);
  J1.icGS = J1.cc.cGS * der(J1.vGS);
  J1.igsgmin = 1e-012 * (J1.G.v - J1.Sinternal);
  J1.igdgmin = 1e-012 * (J1.G.v - J1.Dinternal);
  J1.G.i = J1.icGD + J1.icGS + J1.cc.iGD + J1.igdgmin + J1.cc.iGS + J1.igsgmin;
  J1.D.i = J1.ird;
  J1.S.i = J1.irs;
  0.0 = (-J1.ird) + J1.cc.idrain - J1.cc.iGD - J1.igdgmin - J1.icGD;
  0.0 = (-J1.irs) - J1.cc.idrain - J1.cc.iGS - J1.igsgmin - J1.icGS;
  J2.p = Modelica.Electrical.Spice3.Internal.Jfet.jfetRenameParameters(J2.modelcard);
  J2.m = Modelica.Electrical.Spice3.Internal.Fet.fetRenameParametersDev(J2.AREA, J2.OFF, J2.IC_VDS, J2.IC_VGS, J2.UIC, J2.TEMP);
  J2.p1 = Modelica.Electrical.Spice3.Internal.Jfet.jfetInitEquations(J2.m, J2.p);
  J2.p2 = Modelica.Electrical.Spice3.Internal.Jfet.jfetModelLineInitEquations(J2.p1);
  J2.m1 = Modelica.Electrical.Spice3.Internal.Jfet.jfetCalcTempDependencies(J2.m, J2.p2);
  J2.cc = Modelica.Electrical.Spice3.Internal.Jfet.jfetNoBypassCode(J2.m1, J2.p2, J2.m_type, false, {J2.G.v, J2.Dinternal, J2.Sinternal});
  J2.vGD = J2.G.v - J2.Dinternal;
  J2.vGS = J2.G.v - J2.Sinternal;
  J2.ird * J2.p2.m_drainResist = J2.D.v - J2.Dinternal;
  J2.irs * J2.p2.m_sourceResist = J2.S.v - J2.Sinternal;
  J2.icGD = J2.cc.cGD * der(J2.vGD);
  J2.icGS = J2.cc.cGS * der(J2.vGS);
  J2.igsgmin = 1e-012 * (J2.G.v - J2.Sinternal);
  J2.igdgmin = 1e-012 * (J2.G.v - J2.Dinternal);
  J2.G.i = J2.icGD + J2.icGS + J2.cc.iGD + J2.igdgmin + J2.cc.iGS + J2.igsgmin;
  J2.D.i = J2.ird;
  J2.S.i = J2.irs;
  0.0 = (-J2.ird) + J2.cc.idrain - J2.cc.iGD - J2.igdgmin - J2.icGD;
  0.0 = (-J2.irs) - J2.cc.idrain - J2.cc.iGS - J2.igsgmin - J2.icGS;
  RC.R * RC.i = RC.v;
  RC.v = RC.p.v - RC.n.v;
  0.0 = RC.p.i + RC.n.i;
  RC.i = RC.p.i;
  ground.p.v = 0.0;
  UDD.v = UDD.V;
  UDD.v = UDD.p.v - UDD.n.v;
  0.0 = UDD.p.i + UDD.n.i;
  UDD.i = UDD.p.i;
  U0.v = U0.V;
  U0.v = U0.p.v - U0.n.v;
  0.0 = U0.p.i + U0.n.i;
  U0.i = U0.p.i;
  assert(v_sin.FREQ > 0.0, ""Frequency less or equal zero"");
  v_sin.v = v_sin.VO + (if time < v_sin.TD then 0.0 else v_sin.VA * exp(-(time - v_sin.TD) * v_sin.THETA) * sin(2.0 * 3.141592653589793 * v_sin.FREQ * (time - v_sin.TD)));
  v_sin.v = v_sin.p.v - v_sin.n.v;
  0.0 = v_sin.p.i + v_sin.n.i;
  v_sin.i = v_sin.p.i;
}}}
I really wonder where the additional 230 equations come from. Any clue?
"	defect	closed	high	2.0.0	New Instantiation		fixed