Appropriate Preconditioner
 

Hi, I am trying to solve a simple 2D Poisson equation of a known function with Neumann boundary condition. I am using a point-by-point meshfree solver, and am testing out on the preconditioned BiCGSTAB method.

I have currently tested out using the Jacobi precond, but the results are not good. Anyone has any recommendation of a good precond? Preferrably one without the need to obtain any transpose matrix or something, as my solver will eventually lead to larger scale, parallel, point-by-point solving. Thanks!