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From: macq@miguel.llnl.gov (Don MacQueen)
Newsgroups: comp.lang.fortran
Subject: Re: randu?
Message-ID: <92266@lll-winken.LLNL.GOV>
Date: 1 Mar 91 21:12:31 GMT
References: <62349@eerie.acsu.Buffalo.EDU> <17397@milton.u.washington.edu> <292@re.ukc.ac.uk>
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In article <292@re.ukc.ac.uk>, trh@ukc.ac.uk (T.R.Hopkins) writes:
|> In article <17397@milton.u.washington.edu> seymour@milton.u.washington.edu (Richard Seymour) writes:
|> >What about RANDU?
|> ><my comments in "<...>" brackets>
|> >source: vax fortran user's guide, aa-d035c-te, for vms v3.0, fort v3.0)
|> >page D-12  "Compatibility: VAX-11 Fortran and PDP-11  Fortran"
|> >
|> >D.3.9  RANDU subroutine
|> >The RANDU subroutine computes a pseudorandom numvber as a single-precision
|> >value uniformly distributed in the range:  0.0 .LE. value .LT. 1.0
|> 
|> 
|> Is this the dreaded randu described on p104 of Don Knuth's Semi-numerical
|> Algorithms as "regrettably, the generator that has actually been used on 
|> such machines (System/370) in most of the world's scientific computing
|> centres for about a decade; its very name RANDU is enough to bring dismay
|> into the eyes and stomachs of many computer scientists! .... the generator
|> fails most 3-dimensional criteria for randomness, and it should never have
|> been used."
|> 
|> Tim

-- 
The Macintosh 3-d point cloud spinning program named MacSpin includes a data set created by randu, and they sure aren't random.
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Don MacQueen
macq@miguel.llnl.gov
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