Actually I have checked the returned element, and it seems that it is not when
executing point_value that the error came out. How can I debug this error?
const Elem *e = (*_locator)(p);
if (e == NULL || e->processor_id() != this->processor_id()) return;
v[0] = _asys->point_value(_Vx_var, p);
v[1] = _asys->point_value(_Vy_var, p);
v[2] = _asys->point_value(_Vz_var, p);
> On Jul 1, 2016, at 4:32 PM, Derek Gaston <fried...@gmail.com> wrote:
>
> 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
> <mailto: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
>> <mailto: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
>> <mailto: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
>> <http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind>
>> [0]PETSC ERROR: or try http://valgrind.org <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
>> <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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