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From: mark@mips.COM (Mark G. Johnson)
Newsgroups: comp.benchmarks
Subject: Ole Swang's benchmark: Sum of Harmonic Series
Message-ID: <44125@mips.mips.COM>
Date: 15 Dec 90 18:08:04 GMT
References: <OLES.90Dec13213301@kelvin.uio.no>
Sender: news@mips.COM
Reply-To: mark@mips.COM (Mark G. Johnson)
Lines: 59

In article <OLES.90Dec13213301@kelvin.uio.no> oles@kelvin.uio.no (Ole Swang) writes:
  >
  >Another easy-to-memorize benchmark is the computation of the sum
  >of the first 10 million terms in the harmonic series.
  >This is a FORTRAN version, it should not be too hard to translate
  >even without f2c :-)
  >
  >      PROGRAM RR
  >      DOUBLE PRECISION R
  >      R=0.0
  >        DO 10 I=1,10000000
  >        R=R+1/DBLE(I)
  >10      CONTINUE
  >      WRITE(*,*)R,I
  >      END

Because the Suns that I have access to, don't have Fortran compilers,
I translated (without f2c :-), giving
	#include <stdio.h>
	main() {
		double	r ;
		int	i ;
		r = 0.0;
		for(i=1; i<=10000000; i++)
		    { r += (1.0/( (double) i ) ) ; }
		printf(" r = %16.7le, i = %d\n", r, i);
	}


>It vectorizes fully on the vectorizing compilers I've tested it on
>(Cray and Convex).  It has the advantage over the bc benchmark that
>it's the same code every time.
>


Adding to Ole's list (user CPU seconds from /bin/time),


>Cray X/MP 216               0.29  *
 MIPS RC6280                 3.3            {added}
 MIPS RC3230 Magnum          8.1            {added}
>Convex C 120                8.7
 Sun SPARCstation II        10.0            {added}
>DECstation 5000/200        10.5
>DECsystem 5400             13.1
 Sun SPARCstation 1+        33.0            {added}
>VAX 6330/VMS5.3 FPA        41.9
>VAX 8650/VMS5.3 FPA        55.3
>VAX 8600/VMS5.2 FPA        77.1
>Sun 3/60 (m68881)         105.6
>
>
>* The code was modified to single presicion for the Cray, as this
>yields the wanted 64-bits accuracy.
>
-- 
 -- Mark Johnson	
 	MIPS Computer Systems, 930 E. Arques M/S 2-02, Sunnyvale, CA 94086
	(408) 524-8308    mark@mips.com  {or ...!decwrl!mips!mark}