[petsc-users] Block ILU with AIJ matrix?

Xiaoye S. Li xsli at lbl.gov
Mon Oct 31 01:33:06 CDT 2011


The ILUTP in SuperLU (4.2 and up) exploits blocking (supernodes) in
the (approximate) L & U factors.  Note the block boundary is
discovered on the fly, which is usually larger than the block size
from the input matrix A.  So the efficiency is pretty good.  It uses
threshold dropping with partial pivoting, numerically is quite good
too.    It's available only in the serial version.

Sherry Li


On Sun, Oct 30, 2011 at 11:18 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
> On Sun, Oct 30, 2011 at 23:50, Gong Ding <gdiso at ustc.edu> wrote:
>>
>> I had also considered use max block size. But it is not efficient here.
>> Hope petsc support nonuniform block size one day.
>
> Inodes do a sort of partial blocking. There has to a clear performance
> benefit to explicit variable blocking in order to justify the implementation
> and interface complexity. I have not yet seen a demonstration of this.


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