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Re: Off-by-one error when solving integer linear program
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From: |
Michael Hennebry |
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Subject: |
Re: Off-by-one error when solving integer linear program |
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Date: |
Tue, 17 Dec 2019 22:40:20 -0600 (CST) |
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User-agent: |
Alpine 2.20 (DEB 67 2015-01-07) |
On Tue, 17 Dec 2019, Matthew Keeter wrote:
I used GLPK to solve a problem in this year?s Advent of Code [1], and noticed
that it produces a very slightly wrong answer for one of the examples.
As noted elsewhere, an upper bound of a trillion
requires more precision than GLPK will normally require.
I do not get an integer objective.
I'm really confused about what problem is being solved.
The given ILP does not resemble the problem of producing one unit of fuel.
For the puzzle data I found, one would have 59 variables (columns),
one for each reaction.
I saw mention of more than one part,
so I expect I am missing something.
It?s an integer linear programming problem, pasted below the fold in CPLEX LP
format.
The correct answer is 82892753, and I?m getting 82892752.
The correct answer is 82,892,753.14 .
--
Michael address@hidden
"Sorry but your password must contain an uppercase letter, a number,
a haiku, a gang sign, a heiroglyph, and the blood of a virgin."
-- someeecards