def solve_system(self, rhs, factor, u0, t):
"""
Simple linear solver for (I-dtA)u = rhs using GMRES
Args:
rhs (dtype_f): right-hand side for the nonlinear system
factor (float): abbrev. for the node-to-node stepsize (or any other factor required)
u0 (dtype_u): initial guess for the iterative solver (not used here so far)
t (float): current time (e.g. for time-dependent BCs)
Returns:
dtype_u: solution as mesh
"""
b = rhs.values.flatten()
cb = Callback()
sol, info = gmres(self.Id - factor * self.M,
b,
x0=u0.values.flatten(),
tol=self.params.gmres_tol_limit,
restart=self.params.gmres_restart,
maxiter=self.params.gmres_maxiter,
callback=cb)
# If this is a dummy call with factor==0.0, do not log because it should not be counted as a solver call
if factor != 0.0:
self.gmres_logger.add(cb.getcounter())
me = self.dtype_u(self.init)
me.values = unflatten(sol, 4, self.N[0], self.N[1])
return me
def f_fast_solve(self, rhs, alpha, u0):
cb = Callback()
sol, info = gmres(self.problem.Id - alpha * self.problem.M,
rhs,
x0=u0,
tol=self.problem.params.gmres_tol_limit,
restart=self.problem.params.gmres_restart,
maxiter=self.problem.params.gmres_maxiter,
callback=cb)
if alpha != 0.0:
self.logger.add(cb.getcounter())
return sol