topic Brief question on ILU and OpenMP in Intel® oneAPI Math Kernel Library

Brief question on ILU and OpenMP

Riccardo_Rossi — Wed, 08 Sep 2010 07:29:49 GMT

Hello everyone,

i am writing here to ask about the MKL implementation of the ILU0 and ILU(k) preconditioners:

are they OpenMP parallel? if so ... only the factorization is parallel or also the "triangular" solves?

what kind of techniques is used inside? is it a multi-level ilu ...

i am asking as the parallelization of the iterative solvers is not difficult, but the parallelization of the solve phase of the ILU is highly non-trivial

thank you in advance

Riccardo

Brief question on ILU and OpenMP

Gennady_F_Intel — Wed, 08 Sep 2010 10:54:53 GMT

Riccardo, both of these preconditioners are not threaded at this moment..

--Gennady

Brief question on ILU and OpenMP

Riccardo_Rossi — Wed, 08 Sep 2010 12:17:50 GMT

A shame ...

is there any plan to have it parallel in future releases of MKL?

in any case thank you for the quick reply

Brief question on ILU and OpenMP

Gennady_F_Intel — Wed, 08 Sep 2010 14:08:18 GMT

yes, we are working on this issue, but I cannot say in when this feature will available.

--Gennady

Brief question on ILU and OpenMP

red_cat — Tue, 10 Jan 2012 08:52:01 GMT

At what stage is the development of this functions?Will the added functions for complex matrices?

Brief question on ILU and OpenMP

red_cat — Mon, 23 Jan 2012 09:09:56 GMT

I am interested in - the developers read this forum?

Brief question on ILU and OpenMP

styc — Mon, 23 Jan 2012 22:28:30 GMT

You can use PARDISO instead. Threaded, much stronger than ILU, has built-in CGS.

Brief question on ILU and OpenMP

Riccardo_Rossi — Tue, 24 Jan 2012 08:01:19 GMT

Hello,
this is just to say that pardiso works very nicely and is very fast ... but it is a DIRECT SOLVER!!

ILU is for solving really large systems, which can not be solved directly.
I do understand that it is extremely difficult to write an efficient ILU preconditioner, that's exactly the reason for which i orginally started this thread

Riccardo

Brief question on ILU and OpenMP

Gennady_F_Intel — Tue, 24 Jan 2012 09:07:13 GMT

Hello Riccardo,

1) regarding the original question -we do nothave plans at this time to add this feature to the next release of Intel MKL.

2) qoute: "ILU is for solving really large systems, which can not be solved directly". Riccardo, how about out-of-core version of PARDISO? usage of this mode allow to solve the real big task.

--Gennady

Brief question on ILU and OpenMP

red_cat — Tue, 24 Jan 2012 11:42:28 GMT

I want to use iterative methods (Bi-CG Stab, TFQMR and other) for solving dense linear system. I'm doing at the beginning prefiltration dense matrix to obtain a sparse preconditioner, and then use ILU0 or ILUT algorithm for decomposition.

Since the last post on this

Schaefer__Florian — Sat, 03 Mar 2018 02:43:44 GMT

Since the last post on this topic has been a couple of years ago, I'd like to ask, what is the current state of parallelism for ilu0 preconditioners? Is such a feature on the horizon (or implemented already?).