dolfin team mailing list archive

[Nuno David Lopes <ndl@xxxxxxxxxxxxxx>]

Is there a simple way of setting an initial guess for an Iterative 
LinearSolver? 
In Umfpack and PETSc the default initial guess is the zero vector right?
For time dependent problems it would  be great if one could use the last step 
solutions as the initial guess.
I was thinking of something like
-----------------------------------------
solver.solve(A,x_(n+1),x_n,b)
----------------------------------------- 
where x_n is the initial guess for the iterative solver.
 
Also another doubt, (i'm guessing  that is my math ignorance only)
is it usual that  PETSc::gmres with hypre::amg preconditioner doesn't work.
(After reading that it is so powerfull...)
In a Stokes 566000^2  subsystem it simply blows up with all of the  RAM memory 
(16Gb).   
(I tried it with simpler problems but with bigger systems   and it worked 
perfectly, converging in <10 iterations.)

Sorry for some disturbance in  the troubled-hard-development times you are 
having and thanks again.  

-- 
Nuno David Lopes
http://ptmat.ptmat.fc.ul.pt/%7Endl/ 

Wed Sep 24 18:58:27 WEST 2008