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It's not clear whether this is a bug, but it would be nice to be able to do what is shown in the diagram, which attempts to reproduce via SysPhS a classic Lotka-Volterra System from Modelica University, which has:
model ClassicModel "This is the typical equation-oriented model"
parameter Real alpha=0.1 "Reproduction rate of prey";
parameter Real beta=0.02 "Mortality rate of predator per prey";
parameter Real gamma=0.4 "Mortality rate of predator";
parameter Real delta=0.02 "Reproduction rate of predator per prey";
parameter Real x0=10 "Start value of prey population";
parameter Real y0=10 "Start value of predator population";
Real x(start=x0) "Prey population";
Real y(start=y0) "Predator population";
equation
der(x) = x*(alpha-beta*y);
der(y) = y*(delta*x-gamma);
end ClassicModel;
Note how the 'start' for x is set via a parameter x0.
In the attached SysPhS attempt x0 is assigned via the MagicDraw-specific ElementValue as the default for x, but the export to Modelica does not see it:
model ClassicModel
parameter Real alpha(start=0.1,fixed=true);
parameter Real beta(start=0.02,fixed=true);
parameter Real gamma(start=0.4,fixed=true);
parameter Real delta(start=0.02,fixed=true);
parameter Real x0(start=10.0,fixed=true);
parameter Real y0(start=10.0,fixed=true);
Real x;
Real y;
equation
der(x)=x*(alpha-beta*y);
der(y)=y*(delta*x-gamma);
end ClassicModel;