4 papers
Accurate error estimation in CG
Gérard Meurant, Jan Papež, Petr Tichý
In practical computations, the (preconditioned) conjugate gradient (P)CG method is the iterative method of choice for solving systems of linear algebraic equations with a re…
On efficient numerical solution of linear algebraic systems arising in goal-oriented error estimates
Vít Dolejší, Petr Tichý
We deal with the numerical solution of linear partial differential equations (PDEs) with focus on the goal-oriented error estimates including algebraic errors arising by an inaccur…
Approximating the extreme Ritz values and upper bounds for the -norm of the error in CG
Gérard Meurant, Petr Tichý
In practical conjugate gradient (CG) computations it is important to monitor the quality of the approximate solution to so that the CG algorithm can be stopped when the requ…
Characterization of half-radial matrices
Iveta Hnetynkova, Petr Tichy
Numerical radius is the radius of the smallest ball with the center at zero containing the field of values of a given square matrix . It is well known that $r(A)\leq \|A\…