incompatibale fields for operation -Error
 

Hey!

I am trying to solve the following equation:
solve ( fvm::laplacian(A,P)==delta*fvm::laplacian(A) );

where units of A - [0 0 0 0 0 0 0]
P - [1 2 -3 0 0 -1 0]
and delta - [1 2 -3 0 0 -1 0]

When I run the solver, it gives me the following error:
incompatible fields for operation
[P] == [A]

From function void Foam::checkMethod(const Foam::fvMatrix<Type>&, const Foam::fvMatrix<Type>&, const char*) [with Type = double]
in file /opt/openfoam5/src/finiteVolume/lnInclude/fvMatrix.C at line 1272


I am not sure why the error shows up, because the dimensions match on both sides of the equation.

Any thoughts?