[zhulianhua]

Hi, dear FOAMers,

I have problems to understand the way OF deal with empty patches when it loops over all patches of a field.

For example in the following code:

 48     forAll(a.boundaryField(), patchi)
 49     {
 50         a.boundaryField().set(patchi, fvPatchField<scalar>::New("fixedGradient", mesh.boundary()[patchi], a));
 51     }
 52
 53     forAll(a.boundaryField(), patchi)
 54     {
 55         fixedGradientFvPatchField<scalar>& aPatch =
 56             refCast<fixedGradientFvPatchField<scalar> >(a.boundaryField()[patchi]);
 57         Info << aPatch << endl;
 58     }
 59

After the first forAll loops, the empty patches is still empty type, as if this loop just ignores the empty patches.

Howevre, the second loops leads to a run time error saying:

--> FOAM FATAL ERROR:
Attempt to cast type empty to type fixedGradient

    From function refCast<To>(From&)
    in file /home/lhzhu/centFOAM/OpenFOAM/OpenFOAM-2.2.x/src/OpenFOAM/lnInclude/typeInfo.H at line 114.

So my problem is :
Why does the first forAll loop ignore the empty patch, while the second doesn't ?


Best regards,

Lianhua