[petsc-users] Question about petsc-3.2-p5/src/ts/examples/tutorials/ex15.c

Dear Hong, Thank you very much for your patient explanations. I got that. Thank you! Feng-Chao 2011-12-28 Feng-Chao Wang Message: 2 Date: Tue, 27 Dec 2011 10:16:10 -0600 From: Hong Zhang hzh...@mcs.anl.gov Subject: Re: [petsc-users] Question about petsc-3.2-p5/src/ts/examples/tutorials

[petsc-users] Question about petsc-3.2-p5/src/ts/examples/tutorials/ex15.c

Dear all, I am working with an example of petsc-3.2-p5/src/ts/examples/tutorials/ex15.c I noticed that in ex15.c, Jtype == 0 means that /* use user provided Jacobian evaluation routine */ Jtype == 1 is for /* slow finite difference J; */ and Jtype == 2 is /* Use coloring to compute finite

[petsc-users] Question about petsc-3.2-p5/src/ts/examples/tutorials/ex15.c

Feng-Chao, Jtype == 1 is for /* slow finite difference J; */ computes dense Jacobian one column at a time, taking prohibitively long time for large matrices. For 101*101 matrix, i.e., it evaluates 1.e+4 columns (evaluate function 1.e+4 times). Running it on my Mac, the execution terminates after a