[petsc-users] -snes_type test vs -snes_mf

[(Rebecca) Xuefei YUAN]

Dear all,

I ran a code for np=1 and np=2.

If hand coded Jacobian is provided, np=1 and np=2 gives me different  
convergence and solutions, so I want to know what is wrong.

If option -snes_mf is used, np=1 and np=2 gives me the same  
convergence and close solutions. I thought there might be a bug in  
FormJacobian().

If option -snes_type test is used, np=1 and np=2 gives different ratio  
and differences for finite difference Jacobian(fd) and hand coded  
Jacobian(hc): J_np1_hc = J_np2_hc, but J_np1_fd != J_np2_fd. so I  
thought there might be a bug in FormFunction().

I am not sure which one should be my focus?

Any suggestions?

Thanks a lot!

Rebecca




-- 
(Rebecca) Xuefei YUAN
Department of Applied Physics and Applied Mathematics
Columbia University
Tel:917-399-8032
www.columbia.edu/~xy2102