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Article #178Prehistoric BC Bug - (nf)
From: Robert Herndon
Date: Wed, 01 Feb 1984 02:00
Date: Wed, 01 Feb 1984 02:00
32 lines
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1391 bytes
#N:umn-cs:1300001:000:745
umn-cs!herndon Jan 31 17:59:00 1984
There is a bug in the BC library. The arc-tangent function ("a")
returns pi/4 for the arctangent of any non-zero number. The cause
of this is a mis-associated "if" statement in the function definition.
The fix for this is to change the definition of the a() function.
The file currently reads:
125a126,128
> if(x==1)
> if(scale<52)
> return(.7853981633974483096156608458198757210492923498437764/1)
The following may be substituted:
126,130d125
> if(x==1) {
> if(scale<52) {
> return(.7853981633974483096156608458198757210492923498437764/1)
> }
> }
Or the lines may be deleted entirely. This will slow down the
evaluation of a(1) substantially but will not otherwise harm the
function.
Robert Herndon
umn-cs!herndon
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site umn-cs.UUCP Path: arc1-ca.pugleaf.net!utzoo!watmath!clyde!burl!we13!ihnp4!stolaf!umn-cs!herndon From: herndon@umn-cs.UUCP (Robert Herndon) Newsgroups: net.bugs Subject: Prehistoric BC Bug - (nf) Message-ID: <410@umn-cs.UUCP> Date: Tue, 31-Jan-84 21:00:53 EST Article-I.D.: umn-cs.410 Posted: Tue Jan 31 21:00:53 1984 Date-Received: Tue, 7-Feb-84 11:02:14 EST Sender: notes@umn-cs.UUCP Organization: Computer Science Dept., U of Minn, Mpls, MN Lines: 33