Handle roots of negative values don't work well

[Vitalij Ruge]

e.g.

  model assertPow
    parameter Real Null = 0;
    Real pow1 = Null^(-0.1);
    Real pow2 = (-abs(sin(time*10)/2))^(-0.1);
  end assertPow;

simulate without assert or warnings.
I would expect some assert/warning

A test(s) for the extra ​lines are missing.

[Lennart Ochel]

Is this just about to handle 0^x with x < 0?

[Vitalij Ruge]

Replying to lochel:

Is this just about to handle 0^x with x < 0?

Why pow1 inside the model 0^(-0.1) return no assert?
I guess inf == inf is true.

BTW. In this case you should move this check inside the first "if case", where you check already has a check for 0^x with x < 0.

[Vitalij Ruge]

I mean |x| < 1

[Vitalij Ruge]

Forget it :D

[Vitalij Ruge]

I make mistake

[Vitalij Ruge]

I have see you PR.
I mean you will have issues with:

  model powAssert
    Real pow2 = (-abs(cos(time*10)/2))^(-0.1);
  end assertPow;

Other tools will return here:
Model error - power: ( -abs(0.5*cos(time*10))) ** (-0.1) = (-0.5) ** (-0.1)

[Vitalij Ruge]

Of the other hand:

model tets
 parameter Real one = 1;
Real pow2 = (-one)^(1/3);
end tets;

will return same error in other modelica tool.

[Vitalij Ruge]

Why

(-1)^(1.1) has an assert see ​PR203
(-0.1)^(1.1) has no assert.

[Vitalij Ruge]

I don't know the right strategie, but this has some potencial for solver issues with e.g. bad startvalues.

[Lennart Ochel]

Fixed with cb732fc280ac2d8940713d8a104c18952a0634da/OMCompiler.
Tests added with ​PR203.

[Martin Sjölund]

Milestone renamed

[Martin Sjölund]

Milestone renamed