Non constant Mass Matrix

[ivolkg]

So i have a set of 10 differential equations in which the mass matrix depends on the solution vector, before trying to attempt creating a class that inherit a mass_matrix kind of like and observer.
I wanted to ask is this possible? since I don't see mass being iterated in Solver

[ikorotkin]

The mass matrix is static in this implementation of the Solver and does not depend on the solution vector and time.
You can define any mass matrix inheriting daecpp::MassMatrix class but it should be constant.

In the updated version of the solver, the mass matrix can depend on time but not on the solution vector.
I'm not planning to add the solution vector dependence yet... But I'll keep this issue open for the user's feedback and discussion.