See src/ksp/ksp/examples/tutorials in petsc-dev http://www.mcs.anl.gov/petsc/developers/index.html If you attach the null space to the matrix then the KSP objects automatically pull them out of the matrix and use them as needed. You don't need to set the value at a single point to fix it. Note it is much simplier in petsc-dev so switch to it.
Barry On Dec 5, 2011, at 8:59 PM, Hailong Xiao wrote: > Hi > > I am solving an elliptic problem with Neumann boundary condition with dmda > routines by snes solver. > I set up the residue by DMDASetLocalFunction. > Besides the way like fix the first value to be one by myself, is there way to > do it by petsc routine? like the KSPSetNullSpace() rountine does? > > -- > Hailong
