Then there are those carefully selected branches from small trees or large bushes that can be trimmed to size... watch out for poison oak!
On 9/20/19 7:59 PM, Carl Tollander wrote: > Welding galvanized steel without proper respirators (even outdoors) > can kill you. Research this carefully. > > How about some nice thick wall pvc? > > Carl > > On Fri, Sep 20, 2019, 17:48 Steven A Smith <sasm...@swcp.com > <mailto:sasm...@swcp.com>> wrote: > > Gary - > > I understand better now... > > I definitely agree that the *most* naive eyeballing methods can be > excruciatingly wasteful. > > I presume that your conduit length requirements are not precise... > that > you might be designing them to allow for leaving the window partially > open but otherwise not subject to intrusion or compromise? That seems > to complicate the problem but may pose opportunities. In particular, > *I* might be looking for solutions which leave me with a *minimum* of > leftover conduit by making them longer than their shortest > possibles in > some cases. Or looking at it the other way, even if you don't need to > leave the windows open much when "locked" a more complete use of the > material might be obtained by relaxing the length a little without > compromising security (if a given window can only be opened a few > inches > for example). > > I will be interested in hearing the results of whatever > optimization (or > satisficing) method you use yields. > > - Steve > > PS. regarding guerin's solution, an alternate would be to measure as > suggested, then cut naively until the remaining spaces are larger than > the remaining pieces. Only *then* does one break out the welder and > begin to piece together as-needed. I don't think these are > equivalent. > It also occurs to me that *2* pieces of conduit (end to end, > unwelded) > in a window channel might be *nearly* as effective as a single piece, > albeit less elegant? > > > Hey Steve. The actual project is nothing elaborate. My house has a > > couple or three dozsen horizontally sliding windows with pretty weak > > locks. Since I've had a couple of break-ins in the past, I decided > > that the easiest way to shore up security for that aspect of the > house > > is to just cut short pieces of 3/4 inch conduit to lay > horizontally in > > the spaces where the windows slide. When I want to open a window, I > > will just stand its conduit piece up, and when I want to "lock" it > > again, just lay it back horizontally. I asked on FRIAM because > instead > > of just eyeballing it and having lots of extra (even potentially > > useful in the future) pieces left over, I'd rather use my (and > > FRIAM's) brain to look at possible ways of optimizing this. Kind of > > fun actually putting my mind to something for a change > (retirement can > > be boring if you're not careful). > > > > On Fri, Sep 20, 2019 at 5:55 PM Steven A Smith <sasm...@swcp.com > <mailto:sasm...@swcp.com>> wrote: > >> Gary - > >> > >> I *patently don't* recommend my method, though it does have some > >> charms. I recently was faced with a similar problem to yours > where I > >> needed to cut and install trim around the perimeter of the room > (with > >> door openings) I just layed hardwood floor in. > >> > >> Rather than go into it in detail (I already did that and > realized it was > >> a TL;DR as usual, so cut it) I will just say that I approach these > >> problems as *satisficing* and *constraint* problems rather than > >> *optimization*. Once I had a candidate layout, I simply > looked at the > >> results and determined that the *waste* was acceptable. > Depending on > >> the circumstances I sometimes prefer to have for example, 2 3' > leftovers > >> rather than 1 5' leftover, other times, vice-versa, depending > on how I > >> might use said leftovers in some future application (or hedging > against > >> a mistake in my measuring/cutting). > >> > >> Care to share what your actual conduit/pipe project is? > >> > >> - Steve > >> > >> > >>> 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 > <mailto: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 <mailto: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 > > ============================================================ > > 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.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