PETSc is getting slower in C++?

[xiaoyin ji]

Hi,

I'm embedding a PETSc solver inside a molecular dynamics program. I
used MATMPIAIJ matrix format and set ksp solver with KSPBICG and
preconditioer as PCBJACOBI. Now the problem is ksp solver is getting
slower and slower for each MD step, at the very beginning it takes
about 1sec, and after 5000 steps the solving part takes up to
10sec.(increasing gradually) However, I've also have an identical
program in Fortran version, which did exactly the same thing and did
not have such problem for over 1000000 steps, th Fortran version
always solve within 1sec. The MPI_Wtime() shows that ksp solver is
exactly the slowing down part. Thanks for any hints.

Best,
Xiaoyin Ji

Department of Material Science and Engineering
North Carolina State University