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From: ingoldsby@calgary.UUCP (Terry Ingoldsby)
Newsgroups: net.micro.amiga
Subject: Re: Floating point libraries
Message-ID: <456@vaxb.calgary.UUCP>
Date: Tue, 21-Oct-86 21:38:13 EDT
Article-I.D.: vaxb.456
Posted: Tue Oct 21 21:38:13 1986
Date-Received: Thu, 23-Oct-86 23:13:58 EDT
References: <8610160630.AA06315@cory.Berkeley.EDU> <417@husc6.HARVARD.EDU> <432@wuphys.UUCP>
Organization: U. of Calgary, Calgary, Ab.
Lines: 35
Keywords: Fortran, Lattice, AmigaBasic
Summary: Double vs Float Benchmarks

In article <432@wuphys.UUCP>, lel@wuphys.UUCP writes:
> 
> I just got my new Absoft F77 compiler last week and have been
> familiarizing myself with it and running benchmarks.  The first
> tests I did were of the included IEEE floating point libraries.
> The 1st tests compare Lettuce, AmigaBasic, and Fortran on just
> multiplication loops.
>           a=1
>           loop i=1 to 100000
>                a=a*1.0001
>           end loop
> Results: (from memory...)
> 
>             Lattice double:  ~120 sec
> 	    Lattice float:   ~180 sec
>             Basic (double):  140 sec
> 	    Basic (float):   115 sec
> 	    Fortran float:   11.5 sec
> 	    Fortran double:  ~26  sec
> 
> The Fortran math library is IEEE compatible.
> Lattice double is faster than Lattice single since it must pad and
> truncate. What surprized me was the agonizing slowness of their
> floating point calculations . . .

If I understand the situation correctly, all floating point
operations in C are performed using double precision
arithmetic (at least unless you have a compiler that
conforms to the new ansii standard).  I don't have an
Amiga, but I presume that Lattice C observes this convention
thus explaining the anomaly.

             Terry Ingoldsby

....!ihnp4!alberta!calgary!ingoldsby