[FRIAM] Optimization problem

[Gary Schiltz]

Steve, that makes my day! Your solution is like Kirk's way of passing
the "Kobayashi Maru" training exercise.
https://en.wikipedia.org/wiki/Kobayashi_Maru

On Fri, Sep 20, 2019 at 6:23 PM Stephen Guerin
<stephen.guerin at simtable.com> wrote:
>
> Algorithm with guaranteed optimal:
>
> purchase ceil(TotalLengthNeeded / 6)  tubes
> Weld purchased tubes into one long tube *
> Cut what you need in any order
>
>    * assumes welder $ < optimization design and compute time
> _______________________________________________________________________
> Stephen.Guerin at Simtable.com
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>
> On Fri, Sep 20, 2019 at 1:56 PM Gary Schiltz <gary at naturesvisualarts.com> wrote:
>>
>> Thanks for the links, Peter. I will probably use that software or
>> similar, to get a quick solution, then look at the MOOCs.
>>
>> On Fri, Sep 20, 2019 at 2:52 PM Pieter Steenekamp
>> <pieters at randcontrols.co.za> wrote:
>> >
>> > Two possible approaches are:
>> > a) Solve the problem yourself. Use one or a combination of standard algorithms ( eg you mentioned linear programming and greedy algorithms, there are many more of course) and/or your own custom algorithm. If you wish to go this route and want to learn about the subject, I recommend the series of MOOCS by Stanford's Tim Roughgarden https://www.coursera.org/specializations/algorithms
>> > Or, I think yours is probably a knapsack -type problem and the MOOC https://www.coursera.org/learn/discrete-optimization covers that relatively well.
>> > b) But if you just want to get the solution you can use optimization software like https://www.ibm.com/za-en/products/ilog-cplex-optimization-studio (they have a free edition that will be good enough for your application) will solve it for you without you necessarily knowing how the software does it.
>> >
>> > On Fri, 20 Sep 2019 at 21:00, Gary Schiltz <gary at naturesvisualarts.com> wrote:
>> >>
>> >> I'd like advice on possible ways to solve the following problem
>> >> (plumbers must surely face this all the time). I need to cut a set of
>> >> metal tubes of varying lengths from standard length (6 meter)
>> >> galvanized conduit stock. The goal is to find the number of tubes I
>> >> need to buy, and the order of cuts to produce the minimum amount of
>> >> leftover, unused tube.  I'm interested in what types of solutions
>> >> people use for similar 1-dimensional problems, e.g. linear
>> >> programming, greedy algorithms, etc. (I've been Googling). I'm only
>> >> looking to cut around 15-25 pieces, so my gut feeling is that an
>> >> exhaustive search of all possible solutions, though probably NP-hard,
>> >> would be feasible to perform. Working programs, as well as libraries
>> >> in any language would be a bonus.
>> >>
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>
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