http://courses.engr.illinois.edu/cs554/fa2011/notes/petscpde.pdf has a "this is a simple but inefficient way to set up the matrix" at slide 18. Later they set it as a stensil instead. What is a recommended example of doing the same with OPENMP in FORTRAN, if I have matrices A_central, A_top, A_bottom, A_left, A_right, containing the stensil items? Svetlana