[petsc-users] Question on matrix assembly

Barry Smith bsmith at petsc.dev
Sat Aug 15 21:38:19 CDT 2020


   Sajid,

    In the branch barry/2020-08-13/matsetvalues-nopreallocation-seqaij I have provided a new function
MatSeqAIJSetTotalPreallocation() that requires only a single estimate for the entire number of nonzeros
in the matrix (not row by row). If you provide the rows in order with sorted column indices for each 
row the assembly process will be super fast and you won't need to compute anything twice.

   Barry


> On Aug 14, 2020, at 2:59 PM, Sajid Ali <sajidsyed2021 at u.northwestern.edu> wrote:
> 
> Hi Barry, 
> 
> All entries for a row are available together, but there is no requirement to compute them in order.
> 
> Thank You, 
> Sajid Ali | PhD Candidate
> Applied Physics
> Northwestern University
> s-sajid-ali.github.io <http://s-sajid-ali.github.io/>
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