On Thu, Nov 24, 2011 at 5:37 AM, behzad baghapour < behzad.baghapour at gmail.com> wrote:
> I meant that to do just one or two step in line search correction and let > the solution goes on even if the error reduction may not reach the desired > tolerance. It may help to reduce the computational cost especially in first > iteration or in almost ill-conditioned situation where the Newton iteration > may not holds the stability or does not lead to correct solution and a > change in preconditioning is needed to overcome the situation. > http://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/SNES/SNESSetMaxNonlinearStepFailures.html Matt > On Thu, Nov 24, 2011 at 2:39 PM, Matthew Knepley <knepley at gmail.com>wrote: > >> On Thu, Nov 24, 2011 at 5:00 AM, behzad baghapour < >> behzad.baghapour at gmail.com> wrote: >> >>> >>> >>> On Wed, Nov 23, 2011 at 4:33 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote: >>> >>>> On Wed, Nov 23, 2011 at 01:06, behzad baghapour < >>>> behzad.baghapour at gmail.com> wrote: >>>> >>>>> for( c=0; c<ne; c++ ) for( p=0; p<tot; p++ ) >>>>> FC->e[c].Q[p] = xx[c*(noe*num)+p]; >>>>> >>>> >>>> You haven't told me about "noe" or "num". Do you mean for this to read >>>> xx[c*tot+p]? >>>> >>> >>> noe is the number of equations (equal to number of flow states) and num >>> is the number of shape functions in element (according to the order of >>> accuracy) >>> >>>> >>>> >>>>> >>>>> ierr = VecRestoreArray( x, &xx ); CHKERRQ( ierr ); >>>>> >>>>> interiorFlux( FC->flw, FC->e ); >>>>> faceFlux ( FC->flw, FC->f, FC->e ); >>>>> >>>> >>>> The first of these should set FC->e (if you are adding into it, then >>>> you need to zero it first) and the second should add into it. >>>> >>> >>> I found that my mistake is that I forgot to set upwind effect in my >>> defined field context. The problem was not stable, it is not related to >>> SNES setup. >>> >>> However, I can't find out the difference between "basic" and >>> "basicnonorms" in line search method. >>> >> >> Basic takes the full Newton step, but checks for decrease. nonorms just >> takes it and moves on. >> >> >>> In addition, Is it possible to set the number of line-search corrections >>> or is just decided by the solver? >>> >> >> You can set a custom line search. I am not sure what you mean by this >> "number of line search correctons" >> >> Matt >> >> >>> Thanks a lot, >>> BehZad >>> >>> >>> >> >> >> -- >> What most experimenters take for granted before they begin their >> experiments is infinitely more interesting than any results to which their >> experiments lead. >> -- Norbert Wiener >> > > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20111124/ff3afca1/attachment.htm>
