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Submitted by : (unknown) at: 2007-11-17T22:14:03-08:00 (9 years ago)
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Originally Savannah bug #9424:

  overview: Bug in handling 0^0 in Axiom
  Submitted by:  David Mentré
  Submitted on:  Tue 06/22/04 at 16:53   

  Category:  algebra Severity:  3 - Normal 
  Originator Name:  David MENTRE
  Summary:  Bug in handling 0^0 in Axiom 
  Original Submission:  After a long thread on axiom-developer, the following concensus was optained:

  Page, Bill writes:
  > On Tuesday, June 22, 2004 6:11 AM Martin Rubey
  > martin.rubey@univie.ac.at wrote:
  > 
  > There is a bug.
  > 
  > 0::CARD ^ 0::CARD
  > 
  > should be 1::CARD

  ok.

  > > except that in
  > > 
  > > Vanuxem Grgory writes:
  > > > In complex(Float) and Complex(SingleFloat), we have to change the
  > > > exponentiation so that
  > > > complex(0,0)^complex(0,0.0)
  > > > or
  > > > complex(0,0)^complex(2,2.0)
  > > > doesn't use log.
  > > 
  > > the *latter* really should give 0?
  > >
  > 
  > No. complex(0,0)^complex(0,0.0) is like 0^0.0 and should
  > return
  > 
  > '0**complex(0,0.0)' is undefined
  > 
  > The message 'log 0 generated' is confusing but technically
  > correct.

  Yes, but complex(0,0)^complex(2,2.0) should be 0.0, shouldn't it?

Example of code trigerring the bug:

fricas
-- should return 1::CARD
0::CARD ^ 0::CARD
>> Error detected within library code: 0^0 not defined for cardinal numbers.

fricas
-- should return '0**complex(0,0.0)' is undefined
complex(0,0)^complex(0,0.0)
>> Error detected within library code: log 0 generated

fricas
-- should return complex(0,0)
complex(0,0)^complex(2,2.0)
>> Error detected within library code: log 0 generated

transferred --billpage, Tue, 03 Jan 2006 13:17:12 -0600 reply
Category: => Axiom Mathematics Severity: => normal Status: => open

mostly fixed... --kratt6, Fri, 28 Dec 2007 14:32:16 -0800 reply
Category: Axiom Mathematics => Axiom Library

Status: open => closed




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