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Re: [Help-glpk] GLPK re-endrant
From: |
Francois Galea |
Subject: |
Re: [Help-glpk] GLPK re-endrant |
Date: |
Sun, 5 Jul 2009 01:49:49 +0300 |
Ali Baharev a écrit :
> Hi,
>
> Once upon a time, I had a discussion with one of the GPULib developers
> and he told me GPUs were not good for the simplex method, because the
> gain is not so significant for sparse matrix-vector operations. (Or at
> least it was what i understood.)
Moreover, the RAM dedicated for GPU's is different, as it is not totally
data-safe. Some bits may change during time, potentially introducing
errors in computations. You cannot implement an exact solver using such
hardware.
In addition, GPUs were historically been designed for computing on
single precision computations. Double precision has recently been
included on most modern GPUs, though.
Finally, modern CPU's also have SIMD instructions (SSE/SSE2/... on
Intel's, Altivec on POWER's) which can be used for data-parallel
operations on a single core. C compilers provide the possibility to uses
such instructions directly in C, through special "function calls" called
'intrinsics'. Though, already-existing software such as GLPK would
require heavy re-rengineering (most data structures and algorithms would
require to be redesigned) to support such a programming model.
--
François Galea
INRIA - Saclay - Batiment N
Parc Orsay Université
4 rue J. Monod F-91893 Orsay Cedex
Tél. : +33 1 72 92 59 24
- Re: [Help-glpk] GLPK re-endrant, (continued)
Re: [Help-glpk] GLPK re-endrant, Andrew Makhorin, 2009/07/03
Re: [Help-glpk] GLPK re-endrant,
Francois Galea <=
Re: [Help-glpk] GLPK re-endrant, Robbie Morrison, 2009/07/08