[petsc-users] TSSetIJacobian question
Mark Adams
mfadams at lbl.gov
Mon Feb 16 09:28:57 CST 2015
Sorry, I was getting "composite" from DMCompositeGetAccessArray, I am
talking about MatNest. I can get the matrices with MatNestSetSubMats....
>
> > ! copy in linear operator
> > call MatCopy(a_ts%FJacobean,Jpre,ierr);CHKERRQ(ierr)
> > ! shift 1 & 2 by 'shift'
> > call MatShift(mat00,shift,ierr);CHKERRQ(ierr) ????
> > call MatShift(mat11,shift,ierr);CHKERRQ(ierr) ????
>
> What does this mean? Why not include the shift while assembling?
>
Perhaps I am using this incorrectly but the shift is added in
"FormIJacobian" and only 2 of the 3 fields have u_t. The rest of the
matrix is linear and not time dependant so I create it once in the setup
and copy it in in FormIJacobian.
Thanks,
Mark
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