[petsc-users] Newton LS - better results on single processor

[zakaryah .]

Well the saga of my problem continues.  As I described previously in an
epic thread, I'm using the SNES to solve problems involving an elastic
material on a rectangular grid, subjected to external forces.  In any case,
I'm occasionally getting poor convergence using Newton's method with line
search.  In troubleshooting by visualizing the residual, I saw that in data
sets which had good convergence, the residual was nevertheless
significantly larger along the boundary between different processors.
Likewise, in data sets with poor convergence, the residual became very
large on the boundary between different processors.  The residual is not
significantly larger on the physical boundary, i.e. the global boundary.
When I run on a single process, convergence seems to be good on all data
sets.

Any clues to fix this?
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20171109/c265bdca/attachment.html>