[petsc-users] Kronecker Product

[Guglielmo, Tyler Hardy]

Thanks Barry,

I saw that function, but wasn’t sure how to apply it since the documentation says that S and T are dense matrices, but in my case all matrices involved are sparse.  Is there a way to work around the dense requirement?

Best,
Tyler

From: Barry Smith <bsmith at petsc.dev>
Date: Monday, January 30, 2023 at 11:12 AM
To: Guglielmo, Tyler Hardy <guglielmo2 at llnl.gov>
Cc: petsc-users at mcs.anl.gov <petsc-users at mcs.anl.gov>
Subject: Re: [petsc-users] Kronecker Product

   Do you need the explicit sparse representation of the Kronecker product? Or do you want to apply it as an operator or solve systems with it? If the latter you can use https://petsc.org/release/docs/manualpages/Mat/MatCreateKAIJ/#matcreatekaij<https://urldefense.us/v3/__https:/petsc.org/release/docs/manualpages/Mat/MatCreateKAIJ/*matcreatekaij__;Iw!!G2kpM7uM-TzIFchu!lSQ9WFlYi6PMdfs3WAfEq4ydgCLZtfDgyFy9PjdLNTisCsHtwmVuukcpIv1J0i1EtiQ$>

  Barry





On Jan 30, 2023, at 12:53 PM, Guglielmo, Tyler Hardy via petsc-users <petsc-users at mcs.anl.gov> wrote:

Hi all,

I am wondering if there is any functionality for taking Kronecker products of large sparse matrices that are parallel?  MatSeqAIJKron is as close as I have found, but it seems like this does not work for parallel matrices.  Any ideas here?

An option could be to make A and B sequential, compute the Kronecker product, C, then scatter C into a parallel matrix?  This seems like a horribly inefficient procedure.  I’m still fairly new to petsc, so thanks for patience :)!

Best,
Tyler

+++++++++++++++++++++++++++++
Tyler Guglielmo
Postdoctoral Researcher
Lawrence Livermore National Lab
Office: 925-423-6186
Cell: 210-480-8000
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