small space step lead to floating point exception

[Barry Smith]

    You need to determine where the floating point exception occurs.  
On some computers
this is easy, just run the code in the debugger and use the debugger  
option to trap floating
point exceptions.  Unfortunately this may not always be possible: in  
that case I would
start with running with -info -snes_monitor -ksp_monitor to see what  
is happening before
the floating point exception that is causing the difficulty.

    Barry

On Aug 24, 2008, at 7:18 AM, Shengyong wrote:

> Hi,
>
> Does anyone happen to meet such convergency problem?  I have  
> implemented a petsc solver
> to simulate driven cavity flow problem. I use petsc to solve the  
> poisson equation. When I set the space step
> dx = 1 or 0.01, it works fine. However, when i tried to simulate a  
> meso scale problem, i set dx = 0.0001, dt = 0.00001.
> I got a error : floating point execption..
>
> Does anyone point me out how to solve this problem ?
>
>
>
>
>
> ong
> Solidification  Simulation Lab,
> State Key Lab of  Mould & Die Technology,
> Huazhong Univ. of Sci. & Tech. China