[petsc-users] MatMatMult with dense matrices.

[James A Charles]

Hi Hong,

You can open up matmatmult_comparison.mat in MATLAB ( load matmatmult_comparison.mat ). That .mat contains A, B, C, and C_MATLAB. I called matmatmult in sequential. We use AIJ when A2 was sparse but at the time of this multiplication everything was dense. 

Thanks,
James


----- Original Message -----
From: "Hong" <hzhang at mcs.anl.gov>
To: "James A Charles" <charlesj at purdue.edu>
Cc: "PETSc users list" <petsc-users at mcs.anl.gov>, dlemus at purdue.edu, "Daniel Mejia" <denphi at denphi.com>, "Tillmann Kubis" <tkubis at purdue.edu>
Sent: Sunday, April 5, 2015 4:25:39 PM
Subject: Re: [petsc-users] MatMatMult with dense matrices.




James: 


I'm multiplying two dense matrices. I compared the results against MATLAB and I am getting different results. Attached you will see a zip that contains a .mat file that has the A, B, and C. C_MATLAB is the multiplication of A*B in MATLAB and C is the PETSc 3.4.3 result. I also attached the .m files A, B, and C that were saved from PETSc. Is there something I'm doing wrong or 


What is the file type of matmatmult_comparison.mat? 
How to read it? 
I need to see how it defers from C.m. 



any reason due to the shape of the matrices that this would fail? If it gives any more information we convert the previous matrix that A is formed of A2 (A = A1*A2) to dense prior to the multiplication using MatConvert. 



It seems both A and B are dense, complex square matrices. 
Did you call MatMatMult() in sequential or parallel? What matrix format did you use? 


Hong