We would need to see the PETSc side of the code to see if there is anything wrong there.
> On Apr 5, 2015, at 3:35 PM, James A Charles <[email protected]> wrote: > > 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" <[email protected]> > To: "James A Charles" <[email protected]> > Cc: "PETSc users list" <[email protected]>, [email protected], "Daniel > Mejia" <[email protected]>, "Tillmann Kubis" <[email protected]> > 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
