The removal of critical slowing down

J. Brannicka, R. C. Browerbc, S. F. McCormicke, T. A. Manteuffele, J. C. Osbornbd and C. Rebbibc a Department of Mathematics, The Pennsylvania State University, 221 McAllister Building, University Park, PA 16802, USA b Center for Computational Science, Boston University, 3 Cummington St, MA 02215, USA c Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA d Argonne Leadership Computing Facility, 9700 S. Cass Avenue, Argonne, IL 60439, USA e Department of Applied Mathematics, Campus Box 526, University of Colorado at Boulder, Boulder, CO 80309, USA