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orenlivne / lamg

Lean Algebraic Multigrid
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LAMG Vs. MATLAB's Solvers #1

Open RoyiAvital opened 10 years ago

RoyiAvital commented 10 years ago

Hello, How does LAMG compares to MATLAB's solvers (mldivide and pcg) in performance?

I'm looking to solve $ A x = b $ where $ A $ is very large sparse symmetric positive definite matrix.

Thank You.

orenlivne commented 10 years ago

Hi Roy,

It depends. If A (n x n) is large enough then LAMG's complexity should be O(n) whereas mldivide is O(n^3), but with a smaller hidden constant. Try a few small and increasingly larger versions of A to get a sense for the performance gain.

Oren

On Wed, Jun 4, 2014 at 4:27 AM, RoyiAvital notifications@github.com wrote:

Hello, How does LAMG compares to MATLAB's solvers ([mldivide][ http://www.mathworks.com/help/matlab/ref/mldivide.html] and [pcg][ http://www.mathworks.com/help/matlab/ref/pcg.html]) in performance?

I'm looking to solve $ A x = b $ where $ A $ is very large sparse symmetric positive definite matrix.

Thank You.

— Reply to this email directly or view it on GitHub https://github.com/orenlivne/lamg/issues/1.

RoyiAvital commented 10 years ago

Hi @orenlivne, The problem is make doesn't woek on my system. I'm using Windows 8.1 64 Bit, MATLAB R2014a 64 Bit and Visual Studio 2013.

There's a problem using the eval command (with the cd command).

Once it works I'd be happy to show the performance in my cases.

orenlivne commented 10 years ago

Hi Royi,

I would like to help (although I don't have much time to work on this project so please forgive my slow responses). Can you please email me the stack trace/error message you're getting when you type make('compile')?

This should work - I believe i tested it with your system spec.

Thank you and sorry for the trouble. Oren

On Wed, Jun 4, 2014 at 8:20 AM, RoyiAvital notifications@github.com wrote:

Hi @orenlivne https://github.com/orenlivne, The problem is make doesn't woek on my system. I'm using Windows 8.1 64 Bit, MATLAB R2014a 64 Bit and Visual Studio 2013.

There's a problem using the eval command (with the cd command).

— Reply to this email directly or view it on GitHub https://github.com/orenlivne/lamg/issues/1#issuecomment-45089047.