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Article #12217

Re: More on Linpack pivoting: isamax and instruction set design

#12217
From: Mike McNamara
Date: Fri, 21 Jun 1991 17:24
22 lines
1852 bytes
	Ah, I see I posted too soon.  I now understand that the
discussion is about linpack's IDAMAX routine.  I think the current
champion hardware for this loop is the ardent titan vector unit.  It
has the DRAMAX instruction. This is translated Double precision
Reduction Absolute MAXimum value instruction.  Run over a vector, it
returns in a scalar the maximum absolute value of that vector. 
	( The machine supports the single precision, minimum absolute
value, and non absolute variants, just so no one would think the
instruction was inserted just for Dongarra.  :-)

	Of course, the failing is that IDAMAX doesn't care
particularily about the actual maximum value; it only wants to know
the *index* of that value.  But then a DVCEQ instruction is fully
vectorized also...

	-mac
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Message-ID: <MAC.91Jun21102405@gold.kpc.com>
Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!kpc.com!ardent!mac
References: <396@validgh.com> <1991Jun13.234834.22970@neon.Stanford.EDU> <1991Jun14.134338.4673@linus.mitre.org> <6357@goanna.cs.rmit.oz.au>

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!kpc.com!ardent!mac
From: mac@gold.kpc.com (Mike McNamara)
Newsgroups: comp.arch
Subject: Re: More on Linpack pivoting: isamax and instruction set design
Message-ID: <MAC.91Jun21102405@gold.kpc.com>
Date: 21 Jun 91 17:24:05 GMT
References: <396@validgh.com> <1991Jun13.234834.22970@neon.Stanford.EDU>
 <1991Jun14.134338.4673@linus.mitre.org> <6357@goanna.cs.rmit.oz.au>
Sender: uucp@kpc.com (UNIX-to-UNIX Copy)
Reply-To: mac@ardent.com (Michael McNamara)
Organization: Kubota Pacific Computer Incoporated, Santa Clara, CA
Lines: 22
In-Reply-To: ok@goanna.cs.rmit.oz.au's message of 16 Jun 91 09:07:19 GMT
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