[petsc-users] KSPBuildSolution

[Juha Jäykkä]

> SNESSolve uses a Newton method so the linear system is being solving for a

So the "solution" in the KSP should actually be identically zero for a 
converged result?

> defect. If the initial guess is zero, then it would normally pick up your
> Dirichlet boundary conditions on the first iteration and all subsequent
> solves would have zero in those locations.

It is not zero initially. But, on the other hand, it has zeros at both ends 
even at the very first iteration. If I understood your reply correctly, this 
would be expected for an initial guess which has correct values at the 
boundaries and it should only pick them up on the first iteration if they were 
not correct to begin with.

Having ruled out a possibility of a bug in KSP, I need to continue my hunt for 
DIVERGED_LINEAR_SOLVE... None of the convergence tolerances seem to make any 
difference, it always diverges. The funny thing is, it diverges even if I 
start with an *exact* *solution*... 

Cheers,
Juha

-- 
		 -----------------------------------------------
		| Juha Jäykkä, juhaj at iki.fi			|
		| http://www.maths.leeds.ac.uk/~juhaj		|
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