PETSc Users Manual by Balay, S, Abhyankar, S, Adams, M, Brown, J, Brune, P, Buschelman, K, Dalcin, L, Dener, A, Eijkhout, V, Gropp, W, Karpeyev, D, Kaushik, D, Knepley, M, May, D, McInnes, L, Mills, R, Munson, T, Rupp, K, Sanan, P, Smith, B, Zampini, S, Zhang, H, Zhang, H