[petsc-dev] [petsc-maint #89809] 3D DMDAs in petsc-3.2

[Richard Katz]

> summary:     cruft to handle the special case of solving a 2D problem in a 3D algorithm with stencil size > 1.  This only works in the 3D case, z-dimension

This sounds rather suspicious to me.

> the second layer of ghost points uses the first layer instead of getting the second layer.

I think this may be what is causing a problem in my code:

(gdb) n
28        ierr = DMDAGetGridInfo(user->dav,&is,&js,&ks,&ie,&je,&ke,0,0,0,0);CHKERRQ(ierr);
(gdb) print ks
$1 = 0
(gdb) print ke
$2 = 7
(gdb) print v[8][5][5].u
$5 = 0.071731334082415735
(gdb) print v[7][5][5].u
$6 = 0.071731334082415735

it seems to only occur on the k+ processor boundary (when the next processor is in the k+ direction)

Cheers
Rich





> 
> Since I don't understand your /* 2d case */ business I leave it to you to fix
> 
> I don't understand it either and haven't tried. Maybe Ethan can take a look.
> 

________________________________
Richard Foa Katz
Dept Earth Sciences, Univ Oxford
http://foalab.earth.ox.ac.uk