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[bug] condition of an if-statement in an algorithm
[bug] condition of an if-statement in an algorithm
I just reported this bug for JModelica here in the PyFMI GitHub repository, but then I realized that OpenModelica also has then the same issue. Consider this simple code:
Code:
//test_1.mo
model test_1
//parameters
Real firstVar;
Real secondVar;
Real thirdVar;
algorithm
firstVar := 1.0 * sin(time);
secondVar := abs(firstVar);
if (firstVar < secondVar) then
thirdVar := 1;
else
thirdVar := -1;
end if;
annotation(
experiment(StartTime = 0, StopTime = 10, Tolerance = 1e-08, Interval = 0.02),
__OpenModelica_simulationFlags(lv = "LOG_STATS", outputFormat = "mat", s = "dassl"));
end test_1;
that results in:
click on the image to see the complete picture
which doesn't make sense. The "thirdVar" should return to -1 right after firstVar drops below secondVar.
Thank you
Re: [bug] condition of an if-statement in an algorithm
I tried the if-statement in the equations section, the same problem:
Code:
model test_1
//parameters
Real firstVar;
Real secondVar;
Real thirdVar;
algorithm
firstVar := 1.0 * sin(time);
secondVar := abs(firstVar);
equation
if (firstVar < secondVar) then
thirdVar = 1;
else
thirdVar = -1;
end if;
annotation(
experiment(StartTime = 0, StopTime = 10, Tolerance = 1e-08, Interval = 0.02),
__OpenModelica_simulationFlags(lv = "LOG_STATS", outputFormat = "mat", s = "dassl"));
end test_1;
Re: [bug] condition of an if-statement in an algorithm
As I reported on this Tweet, Martin Sjölund replied to my question the Discord group, saying that the noEvent should be used for the conditions of the if-statement. I tested it for both OpenModelica and JModelica both working fine now.
Code:
model test_1
//parameters
Real firstVar;
Real secondVar;
Real thirdVar;
algorithm
firstVar := 1.0 * sin(time);
secondVar := abs(firstVar);
if noEvent(firstVar < secondVar) then
thirdVar := 1;
else
thirdVar := -1;
end if;
annotation(
experiment(StartTime = 0, StopTime = 10, Tolerance = 1e-08, Interval = 0.02),
__OpenModelica_simulationFlags(lv = "LOG_STATS", outputFormat = "mat", s = "euler"));
end test_1;
but anyways it seems like bad behavior to me and I would consider changing this if I were the developer of these projects. At least show the user some warning.
P.S. I kind of knew from past that adding noEvent is a good idea but I was kinda misguided by this answer suggesting that removing noEvent is OK.
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