Missing error message for noEvent of discrete time expressions

[Peter Aronsson]

The following model should give an error message that the argument to noEvent is not a real elementary expression (see spec).

model Test

Real x;
Boolean b;

equation

x=sin(2*3.14*time);
b=noEvent(abs(x) < 0.8);

end Test;

[Martin Sjölund]

There is no such restriction in the spec that I can find. The noEvent applies to all (even zero) real elementary relations in the (composite) expression.

[Peter Aronsson]

The example in section 4.4.4:
See equation for iff1a below.

Boolean off1, off1a;
Real off2;
equation
off1 = s1 < 0;
off1a = noEvent(s1 < 0); // error, since off1a is discrete
off2 = if noEvent(s2 < 0) then 1 else 0; // possible
u1 = if off1 then s1 else 0; // state events
u2 = if noEvent(off2 > 0.5) then s2 else 0; // no state events

[Martin Sjölund]

Thats's an example and non-normative, which means it carries no real relevance except maybe there is an intent this should not be allowed.

Nowhere in the specification does it say why noEvent(s1 < 0) is illegal, which means it is not. Make a ticket on modelica.org to get text that says no discrete relation may exist inside a noEvent clause or that a noEvent expression has to have at least one real continuous relation inside.