You specified p1(fixed=false), but provided no initial equation for it (so the model tries to invent an equation for p1 from p3 since p3 has a binding and p1 does not). And p12 does not have a binding (should be p12 = 33). The following should be the model you specify and follows the specification:

model TestParameterInit

parameter Real p1 = 0;

parameter Real p11 = 100.0;

parameter Real p12 = 33;



parameter Real p2 = if p1 > 0 then p11 else p12;

parameter Real p3 = 3*p1^2;

Real x(start=-1, fixed=true);

equation

  der(x) = p3 *x^2 - p2 *x;

end TestParameterInit;

If you get warnings during initialization, results will vary between Modelica tools and versions.

Thanks for your quick answer. I understand your explanations

I  wrote the second test where I give of a value of p1 master parameter , the compiler works correctly

but really if I compil my first test alone , the results of the compiler (version 1.9.2)  disturb me !!

Best regards

ALAIN_2


class TestParameterInit
parameter Real p1(fixed=false);
parameter Real p11 = 100.0;
parameter Real p12(start=33.,fixed=true);

parameter Real p2 = if p1 > 0 then p11 else p12;
parameter Real p3 = 3*p1^2;
end TestParameterInit;

model TestParameterInit2
extends TestParameterInit(p1=2,p11=1000.);
Real x(start=-1, fixed=true);
equation
  der(x) = p3 *x^2 - p2 *x;
end TestParameterInit2;

maybe here someone can help me..
in my model i need to initialize a Real variable with initial value =0
but this value has to change during the equation procedure

model EX
   Real a = 0;
equation
   a = a+1;
end EX

why it doesn't work??

Your code is equivalent to saying

a = 0;

a = 1;

So it has one equation too many. To create things like counters, check some examples at: http://book.xogeny.com/behavior/discrete/sampling/

so how can i increase the value of "a" by one?

How  about something like that:

[code]
model EX
   Real a, b;
equation
  a = if initial() then 0 else 1;
  when initial() then
   b = a;
  end when;
end EX;
[\code]
Variable b is just there to see that variable a is really in initial point in time 0.

so long.
Willi