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Round-off error in Pardiso

miramin
Beginner
82 Views
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
0 Kudos
2 Replies
mecej4
Black Belt
82 Views
> 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.
Alexander_K_Intel2
82 Views
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
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