Algorithm with guaranteed optimal: 1. purchase ceil(TotalLengthNeeded / 6) tubes 2. Weld purchased tubes into one long tube <https://www.youtube.com/watch?v=ShByF_MBpNI> * 3. Cut what you need in any order
* assumes welder $ < optimization design and compute time _______________________________________________________________________ stephen.gue...@simtable.com <stephen.gue...@simtable.com> CEO, Simtable http://www.simtable.com 1600 Lena St #D1, Santa Fe, NM 87505 office: (505)995-0206 mobile: (505)577-5828 twitter: @simtable On Fri, Sep 20, 2019 at 1:56 PM Gary Schiltz <g...@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 > <piet...@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 <g...@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. > >> > >> ============================================================ > >> FRIAM Applied Complexity Group listserv > >> Meets Fridays 9a-11:30 at cafe at St. John's College > >> to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com > >> archives back to 2003: http://friam.471366.n2.nabble.com/ > >> FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove > > > > ============================================================ > > FRIAM Applied Complexity Group listserv > > Meets Fridays 9a-11:30 at cafe at St. John's College > > to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com > > archives back to 2003: http://friam.471366.n2.nabble.com/ > > FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove > > ============================================================ > FRIAM Applied Complexity Group listserv > Meets Fridays 9a-11:30 at cafe at St. John's College > to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com > archives back to 2003: http://friam.471366.n2.nabble.com/ > FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove >
============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com archives back to 2003: http://friam.471366.n2.nabble.com/ FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove