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bug#41279: 26.3; Calc: sum(gcd(0,n),n,-1,-1) evaluates to -1
From: |
David Ongaro |
Subject: |
bug#41279: 26.3; Calc: sum(gcd(0,n),n,-1,-1) evaluates to -1 |
Date: |
Fri, 15 May 2020 10:44:07 -0700 |
User-agent: |
Microsoft-MacOutlook/16.37.20051002 |
On 15.05.20, 03:19, "Mattias Engdegård" <mattiase@acm.org> wrote:
> Thank you for reporting this. It seems that Calc first simplifies gcd(0,n) to
> n and then computes sum(n,n,-1,-1) = -1.
> We could either make gcd(0,x)=gcd(x,0)=|x|, or try preventing sum from
> simplifying its operand first, or both.
> For the smallest possible change, what about the hack below?
I see, so the simplest reproduction of the bug doesn't involve the sum, but
just the evaluation of gcd(0, x) or gcd(x, 0). Your fix seems sensible to me, I
don't see why you consider it a 'hack'. The simplification gcd(0, x)=gcd(x,
0)=abs(x) seems legit and matches the gcd definition "The largest positive
integer that divides each of the integers".
- bug#41279: 26.3; Calc: sum(gcd(0,n),n,-1,-1) evaluates to -1, David Ongaro, 2020/05/15
- bug#41279: 26.3; Calc: sum(gcd(0,n),n,-1,-1) evaluates to -1, Mattias Engdegård, 2020/05/15
- bug#41279: 26.3; Calc: sum(gcd(0,n),n,-1,-1) evaluates to -1,
David Ongaro <=