How to change the value of an argument of an if-test within the if-scope

Edy · September 29, 2010, 04:57

Hi,

I have a problem which is probably very simple to solve.
In my program, I would like to change, within an if-scope, the value of the variable used in the if-test.
Basically, what i want to do looks like this :

volScalarField Tsub = Tsat - Tb;
if (Tsub <= 0.05)
{
Tsub = 0.0;
}

BHowever, OpenFOAM operator<= should normally take references to constant volScalarField as arguments. But then I cannot modify these arguments within the if-scope...

Thanks in advance.

/Edouard

herbert · September 29, 2010, 07:04

Hi Edy,

you have to do the change element-wise:

Code:

 forAll(Tsub, iCell)
{
    if (Tsub[iCell] <= 0.05)
    {
        Tsub[iCell] = 0.0;
    }
}

Regards,
Stefan

Edy · September 29, 2010, 08:25

Hi Stefan,

It works. It was obviously something quite easy but I am still not very familiar with OF, i just started few days ago and have a lot to learn.

Vielen Dank!

Edy · September 30, 2010, 07:11

Hi,

One more question.
Tsub is defined as a volScalarField with the dimension of temperature. Is it licit to write a test as you wrote though the LHS has a dimension and the RHS is just a scalar: Or should i define a new temperature dimensioned variable equal to 2 for the RHS of the test?

Thanks

September 29, 2010, 04:57	How to change the value of an argument of an if-test within the if-scope	#1
Edy Member Join Date: Sep 2010 Posts: 35 Rep Power: 15	Hi, I have a problem which is probably very simple to solve. In my program, I would like to change, within an if-scope, the value of the variable used in the if-test. Basically, what i want to do looks like this : volScalarField Tsub = Tsat - Tb; if (Tsub <= 0.05) { Tsub = 0.0; } BHowever, OpenFOAM operator<= should normally take references to constant volScalarField as arguments. But then I cannot modify these arguments within the if-scope... Thanks in advance. /Edouard

September 29, 2010, 07:04		#2
herbert Senior Member Stefan Herbert Join Date: Dec 2009 Location: Darmstadt, Germany Posts: 129 Rep Power: 17	Hi Edy, you have to do the change element-wise: Code: forAll(Tsub, iCell) { if (Tsub[iCell] <= 0.05) { Tsub[iCell] = 0.0; } } Regards, Stefan

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September 29, 2010, 08:25		#3
Edy Member Join Date: Sep 2010 Posts: 35 Rep Power: 15	Hi Stefan, It works. It was obviously something quite easy but I am still not very familiar with OF, i just started few days ago and have a lot to learn. Vielen Dank!

September 30, 2010, 07:11		#4
Edy Member Join Date: Sep 2010 Posts: 35 Rep Power: 15	Hi, One more question. Tsub is defined as a volScalarField with the dimension of temperature. Is it licit to write a test as you wrote though the LHS has a dimension and the RHS is just a scalar: Or should i define a new temperature dimensioned variable equal to 2 for the RHS of the test? Thanks