Re: [FRIAM] Optimization problem

While the online don't list their optimization approaches, I suspect they use a simple approximation algorithm instead of a complicated heuristic algorithm. On the bin packing problem, a successful approximation is called "First Fit Decreasing" which is: 1. Sort a list of pipes to cut in decrea

Re: [FRIAM] Optimization problem

Gary, If you want a quick answer to get your task done, I found a few online tools to calculate for you. eg: https://www.kurraglenindustries.com.au/linear-cutting-list-calculator.htm http://cutlist.dotordotdot.com/current https://www.cutlistoptimizer.com/ Then to study the problem later, it

Re: [FRIAM] Optimization problem

Gary, Thanks for posing this problem to the group - it's been fun to have in the back of the mind for a day. I agree with Pieter that this is a kind of knapsack problem for which Dynamic Programming is a popular approach where you would extend to multiple knapsacks. I might approach it with a var

Re: [FRIAM] Optimization problem

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. > >

Re: [FRIAM] Optimization problem

You can splice together conduit pieces with set screw couplers. They're cheap, stable under compression loads, only require a screwdriver to operate, and produce no toxic gases. https://www.homedepot.com/p/Halex-3-4-in-Electrical-Metallic-Tube-EMT-Set-Screw-Coupling-25-Pack-62807B/202288563 -- r

Re: [FRIAM] Optimization problem

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 wrote: > Gary - > > I understand better now... > > I definitely agree that the *most* naive eyeballing

Re: [FRIAM] Optimization problem

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 subje

Re: [FRIAM] Optimization problem

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 wrote: > > Algorithm with guaranteed optimal: > > purchase ceil(TotalLengthNeeded / 6) tubes >

Re: [FRIAM] Optimization problem

Algorithm with guaranteed optimal: 1. purchase ceil(TotalLengthNeeded / 6) tubes 2. Weld purchased tubes into one long tube * 3. Cut what you need in any order * assumes welder $ < optimization design and compute time _

Re: [FRIAM] Optimization problem

Marcus, for the couple of dozen pieces I need to cut, I suspect a purely brute force solution would be adequate. I've only begun to think about what an extremely naive algorithm would look like. On Fri, Sep 20, 2019 at 6:07 PM Marcus Daniels wrote: > > In my experience, general purpose constraint

Re: [FRIAM] Optimization problem

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 piec

Re: [FRIAM] Optimization problem

In my experience, general purpose constraint and SMT solvers tend to have poor performance compared to linear relaxation techniques found in mathematical optimization products like CPLEX (which also have constraints but from a limited repertoire). It depends on the nature of your constraints w

Re: [FRIAM] Optimization problem

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

Re: [FRIAM] Optimization problem

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 wrote: > > Two possible approaches are: > a) Solve the problem yourself. Use one or a combination of standard > algorithms

Re: [FRIAM] Optimization problem

: [FRIAM] Optimization problem 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

Re: [FRIAM] Optimization problem

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,