[Braedan]

To begin i apologize if im unaware for many things as im not that most knowledgeable of everything on openfoam and all of its source code.
I am attempting to modify the ScalarTransportFoam solver for a diffusion of a particular ion concentration. The equation that i need to solver for is;
d/dt (C) = - Div(N) + R;
Where N is the mass transfer flux depending on C
And R is the reaction rate depending on C also.
I have gotten the solver to be able to run only by writing the equation in terms of the time partial derivative of C and the laplacian of C rather than even using the mass transfer flux. Although i should be solving that term explicitly.
Ie. fvm::ddt(C) == -fvm::laplacian(C) + fvOptions;
Does run but obviously not as i want it to.
But i couldnt solve the laplacian explicitly.
fvm::ddt(C) == -fvc::laplacian(C) + fvOptions;

As it gave me the error:
--> FOAM FATAL ERROR:
lowerPtr_ or upperPtr_ unallocated

From function const scalarField& Foam::lduMatrix::lower() const
in file matrices/lduMatrix/lduMatrix/lduMatrix.C at line 269.

Eventually i went to solve the issue with using the mass transfer flux, which is a different issue in its own. Although i came across the same error using;
fvm::ddt(C) == -fvc::div(N) + fvOptions(C);

So i assumed that using this equation (inside fvScalarMatrix), is causing an issue with creating the coefficients of the matrix and therefore a part or all of the matrix is unallocated. I could not seem to find a solver that solved a simple case with only one implicit variable on the LHS, so im not exactly sure how to approach this issue. Ive been stuck for about a month on this issue so any suggestions would be great.
Thank you!

[LuckyTran]

What OpenFOAM are you using? If very old, it can be an old bug. Otherwise, there's just not enough info to determine what's wrong except we can 100% your solver will not work.

Originally Posted by Braedan

So i assumed that using this equation (inside fvScalarMatrix)

What this means? You mean you are declaring a tmp<fvScalarMatrix>? Because that might break it.