P82 · Packing and covering · Classic · Hard

Equal circles in regular polygons · m = 5 · n = 32

Pack n equal circles into the true regular m-gon with centre (1,1), circumradius 1 and first vertex (2,1), maximising their radius.

Instancem = 5 · n = 32
ObjectiveMaximize circle radius

Formal definition

  • ContainerThe editor and certificate normalize to the true regular m-gon with centre (1,1), circumradius 1 and first vertex (2,1). This is a coordinate convention only; scores use the literature's unit-piece scale. Boundary contact is allowed.
  • SubmissionSubmit {radius, placements:[{x,y,turn},…]}, with decimal strings of at most nine places. x,y are centres; circles require turn=0, polygons use turn=tan(θ/2). Coordinates and turn lie in ±4; 0 < radius ≤ 4.
  • ConstraintsExactly n congruent shapes lie wholly in the container with pairwise disjoint interiors. Polygon rotations are independent, not limited to quarter turns.
  • PrecisionInput decimals are exact rationals; regular-polygon vertices are algebraic, not rounded templates. Feasibility has no floating-point tolerance. A finite-decimal certificate is not a continuous optimality proof.
  • ObjectiveCircle radius r, larger is better; the container circumradius is 1.
Open the full editor
VERIFIED CONSTRUCTIONVERIFIED CONSTRUCTION

Getting a feel for it

Source and certificate

External targets are converted with their printed precision; decimal coordinate certificates are separate. Reconstruction loss never lowers the literature target, and a source construction is not automatically an optimality proof.

Source
The record-holding arrangement for Equal circles in regular polygons m = 5 · n = 32, 0.13579361
Current leader

0.13579361

circle radius

Answer sourceEckard Specht
Solution methodPublished reference construction
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Record holder's solver noteNo solver note yet (expand)

The record holder has not shared a solver note yet.

ANSWER FORMAT

How to write your answer

the true regular m-gon with centre (1,1), circumradius 1 and first vertex (2,1)

Submit {radius, placements:[{x,y,turn},…]}, with decimal strings of at most nine places. x,y are centres; circles require turn=0, polygons use turn=tan(θ/2). Coordinates and turn lie in ±4; 0 < radius ≤ 4.

The current leader's answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.326776617",
      "y": "1.233931851"
    },
    {
      "turn": "0",
      "x": "0.326776617",
      "y": "0.962344629"
    },
    {
      "turn": "0",
      "x": "0.326776617",
      "y": "0.597701448"
    },
    {
      "turn": "0",
      "x": "0.367691460",
      "y": "1.502419457"
    },
    {
      "turn": "0",
      "x": "0.528068586",
      "y": "0.780023038"
    },
    {
      "turn": "0",
      "x": "0.547324596",
      "y": "0.439214199"
    },
    {
      "turn": "0",
      "x": "0.572128148",
      "y": "1.078801682"
    },
    {
      "turn": "0",
      "x": "0.592233620",
      "y": "1.349643683"
    },
    {
      "turn": "0",
      "x": "0.684092697",
      "y": "1.605224451"
    },
    {
      "turn": "0",
      "x": "0.748750512",
      "y": "0.621387795"
    },
    {
      "turn": "0",
      "x": "0.775660162",
      "y": "0.891638586"
    },
    {
      "turn": "0",
      "x": "0.805804517",
      "y": "0.355861036"
    },
    {
      "turn": "0",
      "x": "0.832126321",
      "y": "1.157290976"
    },
    {
      "turn": "0",
      "x": "0.885921336",
      "y": "1.423497129"
    },
    {
      "turn": "0",
      "x": "0.942387494",
      "y": "1.689149518"
    },
    {
      "turn": "0",
      "x": "1.007045310",
      "y": "0.705312863"
    },
    {
      "turn": "0",
      "x": "1.033954960",
      "y": "0.975563653"
    },
    {
      "turn": "0",
      "x": "1.063912925",
      "y": "0.271364476"
    },
    {
      "turn": "0",
      "x": "1.090421118",
      "y": "1.241216043"
    },
    {
      "turn": "0",
      "x": "1.144216133",
      "y": "1.507422196"
    },
    {
      "turn": "0",
      "x": "1.200682292",
      "y": "1.773074585"
    },
    {
      "turn": "0",
      "x": "1.241396123",
      "y": "0.568056477"
    },
    {
      "turn": "0",
      "x": "1.292249757",
      "y": "1.059488721"
    },
    {
      "turn": "0",
      "x": "1.332416294",
      "y": "0.312175747"
    },
    {
      "turn": "0",
      "x": "1.348715916",
      "y": "1.325141110"
    },
    {
      "turn": "0",
      "x": "1.385865803",
      "y": "0.801418708"
    },
    {
      "turn": "0",
      "x": "1.402510931",
      "y": "1.591347263"
    },
    {
      "turn": "0",
      "x": "1.512879938",
      "y": "0.560562644"
    },
    {
      "turn": "0",
      "x": "1.562050427",
      "y": "1.028388595"
    },
    {
      "turn": "0",
      "x": "1.618516585",
      "y": "1.294040985"
    },
    {
      "turn": "0",
      "x": "1.672514902",
      "y": "0.780281322"
    },
    {
      "turn": "0",
      "x": "1.832149866",
      "y": "1.000000000"
    }
  ],
  "radius": "0.135793610"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer

Instance parameters

{
  "n": 32,
  "sides": 5
}

The current leader's answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.326776617",
      "y": "1.233931851"
    },
    {
      "turn": "0",
      "x": "0.326776617",
      "y": "0.962344629"
    },
    {
      "turn": "0",
      "x": "0.326776617",
      "y": "0.597701448"
    },
    {
      "turn": "0",
      "x": "0.367691460",
      "y": "1.502419457"
    },
    {
      "turn": "0",
      "x": "0.528068586",
      "y": "0.780023038"
    },
    {
      "turn": "0",
      "x": "0.547324596",
      "y": "0.439214199"
    },
    {
      "turn": "0",
      "x": "0.572128148",
      "y": "1.078801682"
    },
    {
      "turn": "0",
      "x": "0.592233620",
      "y": "1.349643683"
    },
    {
      "turn": "0",
      "x": "0.684092697",
      "y": "1.605224451"
    },
    {
      "turn": "0",
      "x": "0.748750512",
      "y": "0.621387795"
    },
    {
      "turn": "0",
      "x": "0.775660162",
      "y": "0.891638586"
    },
    {
      "turn": "0",
      "x": "0.805804517",
      "y": "0.355861036"
    },
    {
      "turn": "0",
      "x": "0.832126321",
      "y": "1.157290976"
    },
    {
      "turn": "0",
      "x": "0.885921336",
      "y": "1.423497129"
    },
    {
      "turn": "0",
      "x": "0.942387494",
      "y": "1.689149518"
    },
    {
      "turn": "0",
      "x": "1.007045310",
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    },
    {
      "turn": "0",
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      "y": "0.975563653"
    },
    {
      "turn": "0",
      "x": "1.063912925",
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    },
    {
      "turn": "0",
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      "y": "1.241216043"
    },
    {
      "turn": "0",
      "x": "1.144216133",
      "y": "1.507422196"
    },
    {
      "turn": "0",
      "x": "1.200682292",
      "y": "1.773074585"
    },
    {
      "turn": "0",
      "x": "1.241396123",
      "y": "0.568056477"
    },
    {
      "turn": "0",
      "x": "1.292249757",
      "y": "1.059488721"
    },
    {
      "turn": "0",
      "x": "1.332416294",
      "y": "0.312175747"
    },
    {
      "turn": "0",
      "x": "1.348715916",
      "y": "1.325141110"
    },
    {
      "turn": "0",
      "x": "1.385865803",
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    {
      "turn": "0",
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    {
      "turn": "0",
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    },
    {
      "turn": "0",
      "x": "1.562050427",
      "y": "1.028388595"
    },
    {
      "turn": "0",
      "x": "1.618516585",
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    },
    {
      "turn": "0",
      "x": "1.672514902",
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    },
    {
      "turn": "0",
      "x": "1.832149866",
      "y": "1.000000000"
    }
  ],
  "radius": "0.135793610"
}

Submit {radius, placements:[{x,y,turn},…]}, with decimal strings of at most nine places. x,y are centres; circles require turn=0, polygons use turn=tan(θ/2). Coordinates and turn lie in ±4; 0 < radius ≤ 4. · Verifier v1.0.0

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