Abstract:
All types of PDE can come with Neumann boundary values (B.V.).
Here we are going to address the zero eignevalue of the poisson
operator due to Neumann B.V., related numerical singularity,
the null-space technique to deal with this kind of singularity,
the implementation of the null-space in CG (Conjugate Gradient)
iterative algorithm, stand-alone null-space CG solver for
singular linear systems, and its application in M3D.