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 <[email protected]> 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 <[email protected] > <mailto:[email protected]>> 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 <[email protected] >> <mailto:[email protected]>> 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 <[email protected] >> <mailto:[email protected]>> 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? >> ------------------------------------------------------------------------------ >> Attend Shape: An AT&T Tech Expo July 15-16. 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