subject:"\[petsc\-users\] KSPNormType natural"

Re: [petsc-users] KSPNormType natural

2017-03-13 Thread Jed Brown

"Kong, Fande" writes: > Hi All, > > What is the definition of KSPNormType natural? It is easy to understand > none, preconditioned, and unpreconditioned, but not natural. It is the energy norm. It only makes sense for an SPD operator and SPD preconditioner.

Re: [petsc-users] KSPNormType natural

2017-03-13 Thread Patrick Sanan

This is something that arises with CG and related methods. As in the previous thread, the "left preconditioner" in CG can be though of as an inner product B which allows you to use CG with the Krylov spaces K_k(BA;Bb) instead of K_k(A;b), while retaining the property that the A-norm of the error

[petsc-users] KSPNormType natural

2017-03-13 Thread Kong, Fande

Hi All, What is the definition of KSPNormType natural? It is easy to understand none, preconditioned, and unpreconditioned, but not natural. Fande Kong,