[petsc-users] snessetjacobian question

[Milan Mitrovic]

I use snes for an implicit time stepping scheme... I call it in a loop
for every time step...

the jacobian is recomputed at every step, and the preallocation can
change from time to time... what is the proper way to do it then?
destroy the matrix, then recreate it? what should I do with the
preconditioner matrix? (petsc complains if I dont do P = J)