# \#polyhedra

**URL:** https://discourse.julialang.org/tag/polyhedra/1268.md

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## [How to check the dimension names before eliminating some dimensions of a polyhedron?](https://discourse.julialang.org/t/how-to-check-the-dimension-names-before-eliminating-some-dimensions-of-a-polyhedron/111864)

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**Author:** [@WuSiren](https://discourse.julialang.org/u/WuSiren)\
**Replies:** 3\
**Last updated:** [March 22, 2024, 8:12am UTC](https://discourse.julialang.org/t/how-to-check-the-dimension-names-before-eliminating-some-dimensions-of-a-polyhedron/111864 "2024-03-22T08:12:38Z")

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using Polyhedra using JuMP using CDDLib poly = Model() @variable(poly, -1 \<= x \<= 1) @variable(poly, -1 \<= y \<= 1) P = polyhedron(poly, CDDLib.Library(:exact)) P\_y = eliminate(P, \[1\]) How can I make sure the index \[1\] …

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## [Plotting polyhedron with Makie](https://discourse.julialang.org/t/plotting-polyhedron-with-makie/41306)

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**Author:** [@jerjorg](https://discourse.julialang.org/u/jerjorg)\
**Replies:** 4\
**Last updated:** [November 10, 2023, 3:49pm UTC](https://discourse.julialang.org/t/plotting-polyhedron-with-makie/41306 "2023-11-10T15:49:52Z")

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I am new to Julia and my question and problem may be really simple. I am trying to plot a polyhedron with Makie. I have been following the examples provided by the documentation for the Polyhedra package here and here, b…

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## [How to plot a 3D plot of 3 inequalities?](https://discourse.julialang.org/t/how-to-plot-a-3d-plot-of-3-inequalities/93910)

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**Author:** [@Kanishk](https://discourse.julialang.org/u/Kanishk)\
**Replies:** 10\
**Last updated:** [February 4, 2023, 12:32pm UTC](https://discourse.julialang.org/t/how-to-plot-a-3d-plot-of-3-inequalities/93910 "2023-02-04T12:32:25Z")

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Hello I have 3 inequalities and each have 3 variables. Could you please explain how can I draw a combined one 3D plot with shaded area satisfying all the 3 inequalities? I have inequalities of the form as f1(x,y,z) = a…

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## [QHull and Polyhedra give different volume estimates](https://discourse.julialang.org/t/qhull-and-polyhedra-give-different-volume-estimates/74487)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 0\
**Last updated:** [January 12, 2022, 1:33pm UTC](https://discourse.julialang.org/t/qhull-and-polyhedra-give-different-volume-estimates/74487 "2022-01-12T13:33:45Z")

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I am trying to figure out why QHull and Polyhedra give different volume estimates for the same inputs. They agree in the 2D case, but diverge in the 3D case. Results 2D Polyhedra.jl: 0.982 QHull.jl: 0.982 3D Polyhedra.…

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## [Plotting sets using natural mathematical set expressions](https://discourse.julialang.org/t/plotting-sets-using-natural-mathematical-set-expressions/91582)

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**Author:** [@tapyu](https://discourse.julialang.org/u/tapyu)\
**Replies:** 10\
**Last updated:** [December 13, 2022, 11:10pm UTC](https://discourse.julialang.org/t/plotting-sets-using-natural-mathematical-set-expressions/91582 "2022-12-13T23:10:10Z")

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In convex optimization, it is quite common to come across a n-dimensional set formally written like that, for example, C = \\left\\{ (x\_1, x\_2, \\cdots, x\_n, t) \\in \\mathbb{R}^{n+1} \\mid \\mathbf{x} \\in \\mathbb{R}^{n}, \\lV…

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## [Polyhedron of JuMP model with Polyhedra or Lazyset](https://discourse.julialang.org/t/polyhedron-of-jump-model-with-polyhedra-or-lazyset/89218)

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**Author:** [@papar](https://discourse.julialang.org/u/papar)\
**Replies:** 7\
**Last updated:** [October 26, 2022, 10:53pm UTC](https://discourse.julialang.org/t/polyhedron-of-jump-model-with-polyhedra-or-lazyset/89218 "2022-10-26T22:53:48Z")

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Hello, I want to plot a 3D polyhedron of a JuMP model for education purposes. I have seen these packages Polyhedra and LazySets, but I am unsure how to convert a JuMP model. I believe it requires projection/elimination.…

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## [Minkowski decomposition in Polyhedra.jl](https://discourse.julialang.org/t/minkowski-decomposition-in-polyhedra-jl/77156)

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**Author:** [@XLVII](https://discourse.julialang.org/u/XLVII)\
**Replies:** 1\
**Last updated:** [February 27, 2022, 10:36pm UTC](https://discourse.julialang.org/t/minkowski-decomposition-in-polyhedra-jl/77156 "2022-02-27T22:36:44Z")

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Is there a function about minskowski decomposition or minkowski summands which gives the all summands pair?

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## [Weird Behaviour/Bug in Polyhedra.jl](https://discourse.julialang.org/t/weird-behaviour-bug-in-polyhedra-jl/74168)

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**Author:** [@Codzilla](https://discourse.julialang.org/u/Codzilla)\
**Replies:** 1\
**Last updated:** [January 27, 2022, 1:27am UTC](https://discourse.julialang.org/t/weird-behaviour-bug-in-polyhedra-jl/74168 "2022-01-27T01:27:44Z")

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I observed a strange behaviour with Polyhedra.jl. As a result of a rather complicated algorithm, I obtained a polyhedron as an intersection of half-planes. However, when I want to compute the vertices forming the complex…

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## [Intersection of non-overlapping point clouds with Polyhedra.jl](https://discourse.julialang.org/t/intersection-of-non-overlapping-point-clouds-with-polyhedra-jl/74500)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 4\
**Last updated:** [January 13, 2022, 2:39pm UTC](https://discourse.julialang.org/t/intersection-of-non-overlapping-point-clouds-with-polyhedra-jl/74500 "2022-01-13T14:39:20Z")

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Hi all, I need to identify whether two point “clouds” of arbitrary dimension intersect. As a sanity check, I tested two non-overlapping point clouds to see if the results make sense. Strangely, the intersection is non…

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## [Why is the intersection of a polyhedra with itself not equal to itself?](https://discourse.julialang.org/t/why-is-the-intersection-of-a-polyhedra-with-itself-not-equal-to-itself/72585)

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**Author:** [@XLVII](https://discourse.julialang.org/u/XLVII)\
**Replies:** 7\
**Last updated:** [December 4, 2021, 7:38pm UTC](https://discourse.julialang.org/t/why-is-the-intersection-of-a-polyhedra-with-itself-not-equal-to-itself/72585 "2021-12-04T19:38:42Z")

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using Polyhedra import CDDLib lib = CDDLib.Library() P = polyhedron(vrep(Acolums,Is),lib) #(lines=Acolums , rays = Is) println(intersect(P,P) == P ) # it should be true but it gives false How can it be made to ret…

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## [Is there a polyhedra package that will meet my need](https://discourse.julialang.org/t/is-there-a-polyhedra-package-that-will-meet-my-need/71010)

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**Author:** [@XLVII](https://discourse.julialang.org/u/XLVII)\
**Replies:** 1\
**Last updated:** [November 5, 2021, 3:24pm UTC](https://discourse.julialang.org/t/is-there-a-polyhedra-package-that-will-meet-my-need/71010 "2021-11-05T15:24:22Z")

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I need to implement this algorithm, but need exact same constructor of polyhedra. I don’t know julia, can someone help? or for “I\_s” , rigt kernel of matrix, power set … are there functions for these?

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## [Error using LazySets.plot3d](https://discourse.julialang.org/t/error-using-lazysets-plot3d/52994)

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**Author:** [@adropintheriver](https://discourse.julialang.org/u/adropintheriver)\
**Replies:** 3\
**Last updated:** [January 8, 2021, 6:52pm UTC](https://discourse.julialang.org/t/error-using-lazysets-plot3d/52994 "2021-01-08T18:52:14Z")

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I even did Pkg.update() to ensure i have the latest versions, but still get t using LazySets, Makie, Polyhedra LazySets.plot3d(10. \* rand(Hyperrectangle, dim=3)) MethodError: no method matching iterate(::Polyhedra.Mesh…

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## [JuMP model Polyhedron](https://discourse.julialang.org/t/jump-model-polyhedron/50108)

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**Author:** [@JohnZ](https://discourse.julialang.org/u/JohnZ)\
**Replies:** 11\
**Last updated:** [November 18, 2020, 1:33am UTC](https://discourse.julialang.org/t/jump-model-polyhedron/50108 "2020-11-18T01:33:34Z")

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Hi, I am trying to plot the feasible set of a JuMP model as a 3D figure. I have used the syntax provided in Polyhedra.jl documentation to create a polyhedron: Optimization · Polyhedra A simple example is given below: …

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## [Polyhedra no longer supported?](https://discourse.julialang.org/t/polyhedra-no-longer-supported/30179)

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**Author:** [@squirrel](https://discourse.julialang.org/u/squirrel)\
**Replies:** 1\
**Last updated:** [October 22, 2019, 4:34pm UTC](https://discourse.julialang.org/t/polyhedra-no-longer-supported/30179 "2019-10-22T16:34:05Z")

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Hi. I have Julia v1.2.0 running with Atom v1.40.1. I want to do some Fourier-Motzkin elimination, and I found the CDDLip.jl, and the Polyhedra.jl interface. The Polyhedra documentation says “Polyhedra supports Julia v0.…

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## [Makie and colours](https://discourse.julialang.org/t/makie-and-colours/21937)

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**Author:** [@fa-bien](https://discourse.julialang.org/u/fa-bien)\
**Replies:** 6\
**Last updated:** [March 16, 2019, 1:46pm UTC](https://discourse.julialang.org/t/makie-and-colours/21937 "2019-03-16T13:46:47Z")

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I am visualising polyhedra with Makie. However I find that colours are all way too dark, see MWE that displays a cube that should be the brightest shade of yellow, but is not very bright. Moreover, I find that it gets br…