[petsc-users] [EXT]Re: Is using PETSc appropriate for this problem

[Jed Brown]

Alexander B Prescott <alexprescott at email.arizona.edu> writes:

>>      Are the problems of varying nonlinearity, that is will some converge
>> with say a couple of Newton iterations while others require more, say 8 or
>> more Newton steps?
>>
> The nonlinearity should be pretty similar, the problem setup is the same at
> every node but the global domain needs to be traversed in a specific order.


It sounds like you may have a Newton solver now for each individual problem?  If so, could you make a histogram of number of iterations necessary to solve?  Does it have a long tail or does every problem take 3 and 4 iterations (for example).

If there is no long tail, then you can batch.  If there is a long tail, you really want a solver that does one problem at a time, or a more dynamic system that checks which have completed and shrinks the active problem down.  (That complexity has a development and execution time cost.)