(j3.2006) IEEE modules and NORM2
Thu Oct 9 22:28:35 EDT 2008
May I ask what compiler was used in this study?
RL Fortran Compiler Test
IBM Toronto Lab at 8200 Warden Ave, Markham, On, L6G 1C7
Phone (905) 413-3444 Tie-line 313-3444
email: jimxia at ca.ibm.com
j3-bounces at j3-fortran.org wrote on 10/09/2008 01:51:36 PM:
> [image removed]
> (j3.2006) IEEE modules and NORM2
> Van Snyder
> 10/09/2008 01:54 PM
> Sent by:
> j3-bounces at j3-fortran.org
> Please respond to Van.Snyder, fortran standards email list for J3
> Dick Hanson sent me the following interesting result. It confirms the
> usefulness of the IEEE modules, and points out that when vendors get
> around to implementing NORM2 they shouldn't just use level 1 reference
> As an illustration for using the IEEE modules, I coded up DNRM2
> BLAS. The basic idea is simple: Do the easy loop first and
> check for exceptions and fix things up. For that I used Jim
> 1978 TOMS algorithm. It prompted the question about the static
> The basic conclusions are that this IEEE version is always more
> accurate. It pulls away from Hammarling's LAPACK version at
> n=40 and gets steadily faster, perhaps to factors or 30 or more.
> is on the IBM PowerStation.
> So this is good news for the IEEE module supporters, especially
> Reid. The example he gave in M, R and C for the planar length
> always going to be a lot slower than simply scaling. This is
> there is overhead in the calls to get and set flags. For DNRM2
> overhead time gets swamped out by compute time at about n=40.
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