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Re: [Bug-apl] 0⍟0


From: Juergen Sauermann
Subject: Re: [Bug-apl] 0⍟0
Date: Wed, 13 Jul 2016 13:21:25 +0200
User-agent: Mozilla/5.0 (X11; Linux i686; rv:31.0) Gecko/20100101 Thunderbird/31.4.0

Hi Jay,

I see. Which leaves the question if "equal" shall be strict or within ⎕IO.

Since we are dealing with real numbers (and therefore often rounding errors) within ⎕IO
makes more sense to me but the standard does not mention ⎕IO for .

/// Jürgen


On 07/13/2016 01:05 PM, Jay Foad wrote:
My ISO ("First edition 2001-02-01") says:

Evaluation Sequence:
  If either of A or B are not numbers signal domain-error.
  If A and B are equal, return one.
  If A is one, signal domain-error.
  Set A1 to the natural-logarithm of A.
  Set B1 to the natural-logarithm of B.
  Return B1 divided-by A1.

0⍟0 falls into the "A and B are equal" case.

Jay.

On 13 July 2016 at 11:04, Juergen Sauermann <address@hidden> wrote:
Hi Kacper,

my ISO (June 9, 2000) says DOMAIN ERROR.

More precisely, they say that A⍟B is (⍟A)÷
(⍟B) and then that ⍟0 gives DOMAIN ERROR.

/// Jürgen


On 07/12/2016 11:43 PM, Kacper Gutowski wrote:
According to ISO, 0⍟0 should be one.
GNU APL gives:

      0⍟0
DOMAIN ERROR
      0⍟0
      ^^

-k






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