Got it. Thanks a lot. Regards, Yujie
On Thu, Jul 29, 2010 at 3:32 PM, Barry Smith <bsmith at mcs.anl.gov> wrote: > > On Jul 29, 2010, at 3:30 PM, Yujie wrote: > >> Thanks, Barry. I use X86_64 CPU, do I need to use "--with-64-bit-indices"? > > ? Yes, and when you save the binary matrices you need to make sure the > integers you save into the binary file are 64 bit. (If you use MatView() to > save the matrices this just means that the PETSc uses to save the matrices > has to have been built with --with-64-bit-indices > > ? Barry > >> >> 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 >>> >>> > >
