[FilipeDias93]

Good afternoon
I have recently needed to create some failsafes for my code, such that when a variable is zero, it is replaced by a small value different from zero, like so:

forAll (ENd, c)
{if (End[c]==0)
{ENd[c]=1;}}

However, afterwards I notice that there are still some values that are equal to zero. This occurs on the very first iteration, right before the operation that creates the floating point exception.

Is there a way to include all elements from the mesh? I tried to use mesh.C(), mesh.Sf(), mesh.Cf(), etc. All the ones that are present on the programmers guide, but still there is always a value equal to zero.

Thank you

[Daniel_Khazaei]

Hi,

Can you show us the operation that results in a floating point exception?
Usually this situation can be avoided by proper usage of the SMALL variable which heavily depends on the operation to be performed, for example:

y = x / (x + SMALL)

in your case how the variable ENd is defined? if ENd is defined as a volScalarField then I think this should work:

scalarField& ENdInternal = ENd.internalField();

forAll (ENdInternal, c)
{
    if (ENdInternal[c] == 0)
    {
        ENdInternal[c] = 1;
    }
}

or if you are working with recent OpenFOAM versions:

scalarField& ENdInternal = ENd.primitiveFieldRef();

forAll (ENdInternal, c)
{
    if (ENdInternal[c] == 0)
    {
        ENdInternal[c] = 1;
    }
}

Note: I have just edited your code, I don't know what you are trying to do have any physical meaning.

[FilipeDias93]

Thank you for your help.

The SMALL constant did work, but it would affect the results too much.

As for the second idea, it didn't compile, I believe it was due to the version of OpenFOAM I use.

However, I managed to solve the problem, inspired by the first solution.
The constant that is calculated from ENd should be zero when ENd=0, so I initiated the scalarField =0, and then I placed an if ENd>0 then *expression*.

Thank you for the help

[ELwardi]

I think this is due to some "fixedValue-like" BC setting some values at faces/cells to zero; It's a wild guess as we don't know what End is ... Anyway, this has nothing to do with the simple forAll macro: It only needs something that has a .size() method and an efficient indexing operator/member function to work as a charm. I chaim-lessly refer you to my earlier post on this macro https://foamscience.github.io/forall-openfoam-cpp/