[petsc-users] MatSetValue - Faster if guaranteed local processor?

[Satish Balay]

On Fri, 8 May 2015, Jed Brown wrote:

> Ganesh Vijayakumar <ganesh.iitm at gmail.com> writes:
> 
> > Hello,
> >
> >    Is there any way I can get MatSetValue to run faster if I can guarantee
> > that the entries are local to that processor?
> 
> Use MatSetValuesBlocked if relevant.  Determining on/off process is not
> a bottleneck.  Profile carefully before assuming where the time is
> spent.

The assembly will be most efficient if:

1. preallocation is done correctly

2. most/all entries are local

3. If you can insert values in blocks [and if the block has multiple
colum values - then the col indices are in sorted accending order]

Satish