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From: pmontgom@euphemia.math.ucla.edu (Peter Montgomery)
Newsgroups: comp.sys.alliant
Subject: Re: job classes
Message-ID: <273@kaos.MATH.UCLA.EDU>
Date: 16 Aug 90 23:37:40 GMT
References: <4059@alliant.Alliant.COM> <1990Aug14.115752.23746@eagle.lerc.nasa.gov> <4067@alliant.Alliant.COM> <1990Aug16.125150.19780@eagle.lerc.nasa.gov>
Sender: news@MATH.UCLA.EDU
Organization: UCLA Mathematics Dept.
Lines: 33

C		Even unoptimized programs can use concurrency 
C		instructions.  For example, this program generates
C		calls to library function _vsqrt_fortran, 
C		which tries to do the square roots in parallel.
C		At UCLA, it runs 3.2 times as fast using 
C		a cluster of 6 processors as when running detached.
C		(0.5 vs. 1.6 seconds on an FX/80 with 8 ACEs).

	program test
	implicit none
	integer VECLNG, i, j
	parameter (VECLNG = 5000)
	real vec(VECLNG), tarray(2), ETIME, tbeg, tend
	common vec
	intrinsic SQRT

	tbeg = ETIME(tarray)
	do i = 1, VECLNG
	    vec(i) = i
	end do

	do j = 1, 100
	    vec = SQRT(vec)		! Square root of vector
	end do

	tend = ETIME(tarray)
	print *, 'Execution time = ', tend - tbeg
	end
--
        Peter L. Montgomery 
        pmontgom@MATH.UCLA.EDU 
        Department of Mathematics, UCLA, Los Angeles, CA 90024-1555
If I spent as much time on my dissertation as I do reading news, I'd graduate.