Definitely! Always check that the element returned from a point locator is
owned by the local processor before trying to do anything with it.
If you run in debug mode it should tell you you're trying to access out of
bounds.
Derek
On Fri, Jul 1, 2016 at 5:29 PM 张江 <zhangjiang.d...@gmail.com> wrote:
> The configuration of the machine is
>
> 4X Intel Xeon E7-4820 v2 @ 2.00GHz CPUs
> 1.5TB DDR3 1600Mhz Memory (96x16GB Modules)
>
>
> which can run at most 64 processes. The operating system is 64 bit.
>
> After initialization of mesh, equation system, system and point locator,
> my program use point_locator(point) and point_value() to get the value of a
> point.
> It seems that the error came out after continuously computing several
> points, not when executing point_locator(point) or point_value().
>
> I not not sure whether it is correct that point_locator(point) searches
> the entire mesh space, and point_value() uses the current_local_solution
> (which means the entire dof domain).
> So is that possible to access a value in a parallel vector which does not
> exist on a certain processor?
>
>
> On Jul 1, 2016, at 3:56 PM, Derek Gaston <fried...@gmail.com> wrote:
>
> How much memory do you have on your machine? Do you have more than 48GB?
>
> Are you using a 32bit or 64bit operating system?
>
> Derek
>
> On Fri, Jul 1, 2016 at 2:34 PM 张江 <zhangjiang.d...@gmail.com> wrote:
>
>> Hi,
>>
>> I am trying to read a large data (11.7GB) with libmesh and use it for my
>> application. The program runs well when using just one process.
>> But in parallel (mpirun -n 4), after executing a while, some errors came
>> out:
>>
>> [0]PETSC ERROR:
>> ------------------------------------------------------------------------
>> [0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation,
>> probably memory access out of range
>> [0]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger
>> [0]PETSC ERROR: or see
>> http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind
>> [0]PETSC ERROR: or try http://valgrind.org on GNU/linux and Apple Mac OS
>> X to find memory corruption errors
>> [0]PETSC ERROR: likely location of problem given in stack below
>> [0]PETSC ERROR: --------------------- Stack Frames
>> ------------------------------------
>> [0]PETSC ERROR: Note: The EXACT line numbers in the stack are not
>> available,
>> [0]PETSC ERROR: INSTEAD the line number of the start of the function
>> [0]PETSC ERROR: is given.
>> [0]PETSC ERROR: --------------------- Error Message
>> --------------------------------------------------------------
>> [0]PETSC ERROR: Signal received
>> [0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for
>> trouble shooting.
>> [0]PETSC ERROR: Petsc Release Version 3.7.2, Jun, 05, 2016
>> [0]PETSC ERROR: ./ptracer on a arch-linux2-c-debug named compute001 by
>> jiangzhang Fri Jul 1 10:07:07 2016
>> [0]PETSC ERROR: Configure options
>> --prefix=/nfs/proj-tpeterka/jiang/opt/petsc-3.7.2 --download-fblaslapack
>> --with-mpi-dir=/nfs/proj-tpeterka/jiang/libraries/mpich-3.2
>> [0]PETSC ERROR: #1 User provided function() line 0 in unknown file
>> application called MPI_Abort(MPI_COMM_WORLD, 59) - process 0
>>
>> Anybody know the possible causes?
>>
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