topic Round-off error in Pardiso in Intel® oneAPI Math Kernel Library

Round-off error in Pardiso

miramin — Tue, 13 Sep 2011 21:30:16 GMT

Hi,

I am using Pardiso Direct solver to solve a Stokes problem. (Linear PDE)

The results I get from Pardiso are worng.

If I use an Iterative solver to solve the same exact problem, my output results are correct.

I think it is a matter of precision, or round-off error.

Could you tell me what u think about this matter?

Or how could I make Pardiso to do some iteration, or at least take care of the precision issue?

I am using 16 bit real variables for both of the solvers.

Thanks.
Amin

Round-off error in Pardiso

mecej4 — Tue, 13 Sep 2011 22:24:30 GMT

> I am using 16 bit real variables for both of the solvers.

This cannot be true; did you mean to write "16 byte real" ?

The rest of your conclusions are speculative, and there is no evidence provided to support any of them.

It is possible that you did not use Pardiso correctly.

Round-off error in Pardiso

Alexander_K_Intel2 — Wed, 14 Sep 2011 02:46:15 GMT

Hi Amin,

Could you send to us testcase with compiling line to reproduce your issue? And about Stokes problem: often stiffness matrix of such problem is singular that could be problem for some direct solvers and not a problem some iterative solvers. Is your matrix singular or not?

With best regards,

Alexander Kalinkin