dynamical parameter given in the parameter file. The default is 0 (as before).
In addition the relaxation parameter has been added to the parameter with the
default preserving the state from before.
Also, the default parameter for use_amg and use_bicgstab in the constructor of
CPRPrecondition have been removed.
New parameters are:
- cpr_use_amg (default false) if true, use AMG preconditioner for elliptic part
- cpr_use_bicgstab (default true) if true, use BiCGStab (else use CG) for elliptic part