[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Bug-glpk] wrong answer
From: |
Andrew Makhorin |
Subject: |
Re: [Bug-glpk] wrong answer |
Date: |
Thu, 06 Aug 2015 17:23:58 +0300 |
On Thu, 2015-08-06 at 14:18 +0200, Michal Trněný wrote:
> Here is a simple LP problem that GLPK didn't solve correctly:
> maximize objective: 4*x1 + x2 + 2*x2
> given constraints:
> var x1>=0;
> var x2>=0;
> var x3>=0;
> c1: x1 <= 1;
> c2: x2 <= 1;
> c3: x3 <= 1;
> c4: x1 + x2 + x3 = 2.5;
>
> Solver yielded answer:
> x1=1, x2=1, x3=0.5, obj=7
> that is obviously wrong,
The answer is correct. Please check the last term in your objective.
> because:
> 4*1 + 1 + 2*0.5 != 7 but
> 4*1 + 1 + 2*0.5 = 6
> and this solution (1,1,0.5) isn't optimal, because ...
> there exist solution (1,0.5,1), which objective is 6.5 - bigger, than
> objective of (1,1,0.5).
>
> You may imagine feasible region as unit cube with vertex (1,1,1) cuted
> off.
>
> I'd like you to nottice me, when you fix this bug.
> I want commented pseudocode of GLPK.
> Do you have it? Thank you.
>
> --
> Michal Trněný
> www.michaltrneny.cz
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- Re: [Bug-glpk] wrong answer,
Andrew Makhorin <=