[andrea.pasquali]

Hi,
I'm trying to add the convergence check on forces function following the residuals convergence check in simpleFoam.
For example, for the forces pressure, I added those lines:

scalar eqnResidualFF = 1, maxResidualFF = 0;

eqnResidualFF = solve
(
fm.first().first() += sum(fN)
).initialResidual();

maxResidualFF = max(eqnResidualFF, maxResidualFF);

After compilation I got the error:

error: invalid use of void expression

What I'm wronging? I think it does not like the expression:

+=

Could anyone help me to go ahead?

Thanks

Andrea