fvPatchField<Type>::operator==
 

Howdy Foamers:

Browsing through the uniformFixedValue fvPatchField implementation there is a call to an operator like this in the member function updateCoeffs():

Digging into fvPatchField.C, the function is implemented as follows:

I am familiar with operator overloading C++, but I have never seen operators to be called like this before. I could guess that the == ends up being some kind of assignment. It would be great if someone could provide a more accurate description of what both lines do.

Thanks in advance, Gerry.

Howdy Foamers:

I think it is simply used as an assignment, and based on this OpenFOAM will somehow update the solver coefficients. I didn't dig so deep to see if this is the case but my results seems to tell me something is happening in the right direction.

Gerry.

Hi,

We use operator== to indicate forced assignment, in contrast with normal assignment of an fvPatchField.

Normal assignment is a virtual overload depending on type, where for example it does nothing for a fixedValue derives class.

What the code says is “when forcing assignment, use the op= of the base class for the Field. This is not a virtual hierarchy and it will do the actual assignment job.

Hope this helps,

Hrv

Dear Professor Jasak:

Thank you very much for taking your time to explain this. In the end I went (just a little) deeper to the definition of the overloaded Field assignment operator and it confirmed your comments and my observation.

In the end I would like to use this to assign a Field to the fvPatchField using this variant of the forced assignment operator, that is:

instead of:

I am still in the process of trying to get it to work, as I am still having some problems with referencing my incoming Field. However I think your input has made this much more clear and I believe I know how to proceed.

Thank you again, Gerry.