For my code on a single processor, using the options -ksp_type gmres -pc_type lu
works fine, but -ksp_type gmres -pc_type asm -sub_pc_type lu produces a zero pivot. On one processor I would expect these two to be identical, and in fact when I print out the asm submatrices (there is only one) in the second case and the original matrix in the first case, they are identical. Even stranger is that -ksp_type gmres -pc_type lu -sub_pc_type lu also produces a zero pivot. I would expect it to ignore the sub_pc in this case. Thanks for any help, Andrew --- Andrew T. Barker andrew.barker at colorado.edu Applied Math Department University of Colorado, Boulder 526 UCB, Boulder, CO 80309-0526
