I am trying to express the radiation pattern of an antenna in terms of spherical harmonic basis functions. I have radiation pattern data at N=324360 points. Therefore, my matrix is spherical harmonic basis functions evaluated till order sqrt(N) (which makes up at total of N elements), evaluated at N data points. So this is a linear least squares problem, and I have been trying to solve it by finding its pseudoinverse which uses SVD. The elements of the matrix are complex, and the matrix is non-sparse. I have solved it in MATLAB using a subsample of the data, but MATLAB runs out of memory while calculating the SVD at input matrix size 2500 X 2500. I need to solve this problem using the entire data.
I was thinking of using SLEPc because I found a ready-to-use code which computes the SVD of a complex-valued matrix ( http://www.grycap.upv.es/slepc/documentation/current/src/svd/examples/tutorials/ex14.c.html). I don't know how to use either PETSc or SLEPc (or Elemental) yet, so I am trying to figure out where to start and what I should learn. Thanks, Modhurita On Mon, Dec 19, 2011 at 12:31 PM, Matthew Knepley <knepley at gmail.com> wrote: > On Mon, Dec 19, 2011 at 12:21 PM, Modhurita Mitra <modhurita at > gmail.com>wrote: > >> Hi, >> >> I have to compute the pseudoinverse of a 324360 X 324360 matrix. Can >> PETSc compute the SVD of this matrix without parallelization? If >> parallelization is needed, do I need to use SLEPc? >> > > With enough memory, yes. However, I am not sure you want to wait. I am not > sure how SLEPc would help here. > From the very very little detail you have given, you would need parallel > linear algebra, like Elemental. However, > I would start out from a more fundamental viewpoint. Such as replacing > "compute the psuedoinverse" with > "solve a least-squares problem" if that is indeed the case. > > Matt > > >> >> Thanks, >> Modhurita >> > > > > -- > 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 > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20111219/0366380a/attachment.htm>
