Dear all I am solving 3 coupled first order PDE in 2-D with SNES. The stencil is (3+1+3) in both directions due to weno scheme. I want to use matrix-free gmres. For preconditioner, I will use first order scheme with stencil (1+1+1) in both directions. I am using DMDA.
Two things that I am looking for are: How to setup the matrix ? Since I have 3 variables at each grid point, how to fill the jacobian matrix. Is there an existing example that comes close to this situation. My search was not fruitful. Thank you praveen
