how to re-initialze a contiuous variable which isn't a state

[AHaumer]

The Modelica specification doesn't allow to reinit a continuous variable which isn't a state;
but how should I get the peak value of a signal with respect to predefined periods:

block PosPeak "Positive peak during one period"
  extends Modelica.Blocks.Interfaces.SISO;
  parameter Modelica.SIunits.Frequency f=1 "Basic signal frequency";
protected
  Real x;
equation
  x=max(u,x);
  when sample(0, 1/f) then
    y=x;
    reinit(x,u); // not standard compliant!
  end when;
end PosPeak;

[sebastien]

Replying to AHaumer:

The Modelica specification doesn't allow to reinit a continuous variable which isn't a state;
but how should I get the peak value of a signal with respect to predefined periods:
{{{
block PosPeak "Positive peak during one period"
extends Modelica.Blocks.Interfaces.SISO;
parameter Modelica.SIunits.Frequency f=1 "Basic signal frequency";
protected
Real x;
equation
x=max(u,x);
when sample(0, 1/f) then
y=x;
reinit(x,u); // not standard compliant!
end when;
end PosPeak;
}}}

This model is not correct. "x=max(u, x)" does not constraint x when x >= u. IMO a correct version is:

block PosPeak "Positive peak during one period"

extends Modelica.Blocks.Interfaces.SISO;
parameter Modelica.SIunits.Frequency f=1 "Basic signal frequency";

protected

Real x;

equation

der(x) = if u >= x then der(u) else 0;
when sample(0, 1 / f) then

y = x;
reinit(x, u);

end when;

end PosPeak;

so that x is now a real state.