Horton

Re: Greatest Common Divisor

Vik Fearing <vik.fearing@2ndquadrant.com>

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From: Vik Fearing <vik.fearing@2ndquadrant.com>
To: Fabien COELHO <coelho@cri.ensmp.fr>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Stephen Frost <sfrost@snowman.net>, Dean Rasheed <dean.a.rasheed@gmail.com>, Chapman Flack <chap@anastigmatix.net>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2020-01-04T09:30:55Z
Lists: pgsql-hackers 
On 04/01/2020 09:35, Fabien COELHO wrote:
>>> I'm unsure about gcd(INT_MIN, 0) should error. Possibly 0 would be
>>> nicer?
>>
>>
>> What justification for that do you have?
>
> ISTM that the current implementation has:
>
>   \forall int4 n, n \neq MIN_INT4, \gcd(n, 0) = 0 ?
>
> In which case applying the same rule for min int seems ok. 


No, gcd(n, 0) = n.

-- 

Vik Fearing

Commits

  1. Add functions gcd() and lcm() for integer and numeric types.