[sturgeon]

Hi all

I'm having a minor issue compiling UEqn for a solver I'm working on. I want to add a force and I'm putting it in the momentum predictor, but I've run into a strange problem.

When my code is like this:

volVectorField F("F",Fx*vector(1,0,0)+Fy*vector(0,1,0)+Fz*vector(0,0,1));

surfaceScalarField Ff = fvc::interpolate(F) & mesh.Sf();

    if (pimple.momentumPredictor())
    {
        solve(UEqn == fvc::reconstruct
   (
                (
                     fvc::interpolate(rhok-1)*(g & mesh.Sf())
					+ Ff
					 - fvc::snGrad(p)*mesh.magSf()
                )
				) 
				);

        fvOptions.correct(U);
    }

It compiles fine. However, when it's like this:

volVectorField F("F",Fx*vector(1,0,0)+Fy*vector(0,1,0)+Fz*vector(0,0,1));

    if (pimple.momentumPredictor())
    {
        solve(UEqn == fvc::reconstruct
   (
                (
                     fvc::interpolate(rhok-1)*(g & mesh.Sf())
					+ fvc::interpolate(F) & mesh.Sf()
					 - fvc::snGrad(p)*mesh.magSf()
                )
				) 
				);

        fvOptions.correct(U);
    }

I get a huge stream of errors in the console. But to me they should be functionally identical - however clearly they are not. The only difference is in the version that compiles, the force is interpolated to the faces and stored as a variable Ff, and in the second, this step is skipped in favour of just interpolating the faces within the code for UEqn==.

I know this is minor but I'm interested as to why this error happens to improve my knowledge of C++ and OF development.

Thanks

[Taataa]

The "*" operator is outer product and "&" is inner product and you're adding output of these two operators. So I guess the difference could be because of mismatching of types. In the upper case you declared the type whereas in the lower one the compiler is taking care of that.

[sturgeon]

Originally Posted by Taataa

The "*" operator is outer product and "&" is inner product and you're adding output of these two operators. So I guess the difference could be because of mismatching of types. In the upper case you declared the type whereas in the lower one the compiler is taking care of that.

That makes sense so I guess that could be the issue. I better look into this and make sure the code is doing what I intend.

Thank you!