I second this. How many subdomains for a 1 billion unknown problem? Jie
----- Original Message ----- From: "Jed Brown" <[email protected]> To: "For users of the development version of PETSc" <petsc-dev at mcs.anl.gov> Sent: Friday, March 1, 2013 11:43:35 PM Subject: Re: [petsc-dev] Deflated Krylov solvers for PETSc An alternative description for the method in the paper is "two-level unsmoothed aggregation applied to the ASM-preconditioned operator". When there are many processes/subdomains, the dimension of the coarse space can be huge. Extreme eigenvectors would be more useful, but you would still need a very large number to scale to many subdomains.
