Thanks, Barry. I use X86_64 CPU, do I need to use "--with-64-bit-indices"?
Regards, Yujie On Thu, Jul 29, 2010 at 3:27 PM, Barry Smith <bsmith at mcs.anl.gov> wrote: > > On Jul 29, 2010, at 3:06 PM, Yujie wrote: > >> Dear PETSc developers, >> >> When the program based on PETSc runs in parallel mode, how much size >> of the matrix can MatLoad load? > > ? Currently the limit is that each individual process cannot hold more then 2 > billion nonzeros when using MatLoad(). So if you have more processes you can > hold as big a matrix as you want. Within a few days PETSc-dev will eliminate > this limit (which comes from how we use MPI). > > ?But you need to ./configure PETSc with the option --with-64-bit-indices and > need an operating system that supports 64 bit points (which you likely have). > >> Does the program need to save the whole matrix in one CPU, > > ?No, absolutely NOT. > > > ?Barry > > >> or is each >> CPU in charge of the part of the matrix? >> >> For example, I have one matrix of ~30G. There are two CPUs on each >> nodes with totally16G memory. I have 8 nodes. I use 16CPUs for >> running. Can I load this matrix using MatLoad? Thanks a lot. >> >> Regards, >> Yujie > >
