Preconditioner based on the Chebyshev semi-iteration. In order to provide a linear preconditioner the termination criterion based on relative descent in the energy-norm induced by the preconditioner is disabled here. Instead the preconditioner performs a fixed number of iterations thus yielding a linear preconditioner.
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template<class Operator>
class Kaskade::ChebyshevPreconditioner< Operator >
Preconditioner based on the Chebyshev semi-iteration. In order to provide a linear preconditioner the termination criterion based on relative descent in the energy-norm induced by the preconditioner is disabled here. Instead the preconditioner performs a fixed number of iterations thus yielding a linear preconditioner.
Definition at line 159 of file chebyshev.hh.
Init spectral bounds for the mass matrix arising from tetrahedral discretization of the domain and linear elements.
According to "Wathen: Realistic eigenvalue bounds for the Galerkin mass matrix" the spectrum of the preconditioned mass matrix is contained in \([\frac{1}{2},\frac{5}{2}]\). For chebyshev semi-iteration the bounds on the spectrum are in general given in the form \( [a-b,a+b] \) yielding the coefficients \(a=1.5,\ b=1\). See Wathen,Rees: "Chebyshev semi-iteration in preconditioning for problems including the mass matrix".
Definition at line 133 of file chebyshev.hh.
