Hi, Yes I will try Elemental but there is lots of complex routines and functions with long codes in Matlab which goes in the creation of the A and B matrices, so re-writing in C will take a long time.
Even if Matlab takes 128 GB out of 256 GB, and the matrix A to be written is around 25 GB, then PetscBinaryWrite.m is using more than 100 GB just to run.. This is the problem. so is there any other way ? cheers, Venkatesh On Wed, Jun 10, 2015 at 7:07 PM, Matthew Knepley <[email protected]> wrote: > On Wed, Jun 10, 2015 at 8:32 AM, venkatesh g <[email protected]> > wrote: > >> The size of the matrix is 84500 x 84500 >> >> the no. of non-zero elements is 2.7338e+09 >> > > This matrix is not sparse, it has 40% fill. You should treat it as dense. > For dense matrices of this size, > you should consider using Elemental. We have an interface to Elemental in > PETSc. > > I recommend writing the code to create these entries on the fly since it > will probably be faster than loading > them from disk. > > Thanks, > > Matt > > >> cheers, >> Venkatesh >> >> On Wed, Jun 10, 2015 at 6:35 PM, Satish Balay <[email protected]> wrote: >> >>> Whats the size of the matrix? How many non-zeros? >>> >>> Satish >>> >>> On Wed, 10 Jun 2015, venkatesh g wrote: >>> >>> > Hi >>> > >>> > I am trying to write very large sparse matrices A and B for solving >>> > generalized Eigenvalue problem >>> > >>> > so that I can use SLEPC ex7.c code. >>> > >>> > I want to read matrices from file according to that code. And I >>> generate >>> > these matrices from Matlab using PetscBinaryWrite.m >>> > >>> > However, it exceeds my 256 GB RAM in one of the machines. So I am >>> unable to >>> > generate these binary matrices. >>> > >>> > Kindly let me know how to write them efficiently. >>> > >>> > cheers, >>> > >>> > Venkatesh >>> > >>> >>> >> > > > -- > What most experimenters take for granted before they begin their > experiments is infinitely more interesting than any results to which their > experiments lead. > -- Norbert Wiener >
