Some strange results running in PETSc.

[Barry Smith]

    www.valgrind.org


On Apr 29, 2009, at 10:18 PM, (Rebecca) Xuefei YUAN wrote:

> Hi,
>
> I am running some codes and stores the solution in the text file.  
> However, I found that some results are wired in the sense that some  
> processors are "eating" my (i,j) index and the corresponding solution.
>
> For example, the solution at time step =235 on processor 6 is right,  
> but at time step = 236 on processor 6, one grid solution is missing  
> and thus the order of the index is wrong.
>
> In the attached two files:
> hp.solution.dt0.16700.n90.t235.p6 (right one)
> hp.solution.dt0.16700.n90.t236.p6 (wrong one)
> for example,
>
> in hp.solution.dt0.16700.n90.t235.p6 (right one)
> i      j
> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------
> 50 14 3.3212491928636803e-02 7.2992225179014901e-03  
> 2.9841295384404947e+00 2.2004855368148415e-02
> 51 14 4.0287965701667774e-02 2.5401878231124070e-03  
> 2.9201873761746322e+00 2.6251864239477816e-02
> 52 14 4.7084950235070790e-02 -1.5367647745423544e-03  
> 2.8460826176461214e+00 3.1550405800570377e-02
> 53 14 5.3394938807608198e-02 -3.8189091837479271e-03  
> 2.7618414550374171e+00 3.4078755072804334e-02
> --------------------------------------------------------------------------------------------------------------------------------------------------------------------
> however, in hp.solution.dt0.16700.n90.t236.p6 (wrong one)
> i      j
> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------
> 50 14 3.1239406700376452e-02 8.5179559039992043e-03  
> 2.9840003096148520e+00 2.1760859158622522e-02
> 51 14 3.8032143218986063e-02 3.6341965920997721e-03  
> 2.9198035731818854e+00 2.6200771510346648e-02
> 53 14 5.0661309132451274e-02 -2.9274557377189617e-03  
> 2.7606822480069755e+00 3.4021016413777964e-02
> 54 14 5.6049570141121191e-02 -2.8111244430837979e-03  
> 2.6669503598276267e+00 3.8855104759650566e-02
> --------------------------------------------------------------------------------------------------------------------------------------------------------------------
> the (i,j) = (52,14) is missing and as a result, one grid point  
> solution is missing.
>
> I did not understand how this happens and why this happens?
> Any ideas?
>
> Thanks very much!
>
> Cheers,
>
> Rebecca
>
>
> -- 
> (Rebecca) Xuefei YUAN
> Department of Applied Physics and Applied Mathematics
> Columbia University
> Tel:917-399-8032
> www.columbia.edu/~xy2102
>
> <hp.solution.dt0.16700.n90.t235.p6><hp.solution.dt0.16700.n90.t236.p6>