Backend fails on when equations

[Martin Sjölund]

Backend fails to generate residuals for the following Modelica code:

model WhenValidResult 
  Real x,y; 
equation 
  x + y = 5; 
  when sample(0,2) then 
  y = 7 - 2*x; 
  end when; 
end WhenValidResult;

Note: Changing the problem slightly does change the error messages from the backend.
x = y-5 removes "findDiscreteEquation failed, searching for $x" for example.

From forums: ​http://www.openmodelica.org/index.php/forum/topic?id=64&p=1#p284

[Lennart Ochel]

This is affected by r22641. Now, OpenModelica generates a codegen error similar (but less helpful) to Dymola.

[Martin Sjölund]

This ticket was not closed for 1.9.1, which has now been released. It was batch modified for milestone 1.9.2 (but maybe an empty milestone was more appropriate; feel free to change it).

[Willi Braun]

fixed in r23260.

[Lennart Ochel]

The model from the description only works randomly.
If one changes the order of both equations, the model fails with omc tearing and works with cellier tearing.

[Lennart Ochel]

I think this will be solved properly as soon as I divided the simulation into a continuous system and discrete system.
It would also be possible to adjust the tearing heuristic until then.

[Lennart Ochel]

I changed the example to the following:

model bug1228
  Real x,y;
  Real a,b;
equation
  when sample(0,0.2) then
    y = 7 - 2*x+time;
  end when;
  x + y = 5;

  a + b = 5;
  when sample(0,0.2) then
    b = 7 - 2*a+time;
  end when;
end bug1228;

That one fails with both tearing heuristics.

[Martin Sjölund]

Milestone changed to 1.9.3 since 1.9.2 was released.

[Martin Sjölund]

Moved to new milestone 1.9.4

[Martin Sjölund]

Milestone pushed to 1.9.5

[Martin Sjölund]

Milestone renamed

[Patrick Täuber]

This is fixed in ​#610

[Martin Sjölund]

Milestone deleted