P82 · Packing and covering · Classic · Hard

Equal circles in regular polygons · m = 5 · n = 33

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 = 33
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 = 33, 0.134134799
Current leader

0.134134799

circle radius

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

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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": "0.325117805",
      "y": "1.350304551"
    },
    {
      "turn": "0",
      "x": "0.325117805",
      "y": "0.994762831"
    },
    {
      "turn": "0",
      "x": "0.325117805",
      "y": "0.726493232"
    },
    {
      "turn": "0",
      "x": "0.424592679",
      "y": "0.477348038"
    },
    {
      "turn": "0",
      "x": "0.505448270",
      "y": "1.548923536"
    },
    {
      "turn": "0",
      "x": "0.526030968",
      "y": "1.172533691"
    },
    {
      "turn": "0",
      "x": "0.579528468",
      "y": "0.909652358"
    },
    {
      "turn": "0",
      "x": "0.632654964",
      "y": "0.646695796"
    },
    {
      "turn": "0",
      "x": "0.701440774",
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    {
      "turn": "0",
      "x": "0.709222238",
      "y": "1.368517202"
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    {
      "turn": "0",
      "x": "0.760587821",
      "y": "1.631823401"
    },
    {
      "turn": "0",
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      "y": "1.111877153"
    },
    {
      "turn": "0",
      "x": "0.834696036",
      "y": "0.826838772"
    },
    {
      "turn": "0",
      "x": "0.900847918",
      "y": "0.566853183"
    },
    {
      "turn": "0",
      "x": "0.956688600",
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    },
    {
      "turn": "0",
      "x": "0.964361788",
      "y": "1.451417067"
    },
    {
      "turn": "0",
      "x": "1.015727371",
      "y": "1.714723266"
    },
    {
      "turn": "0",
      "x": "1.034015209",
      "y": "1.006395016"
    },
    {
      "turn": "0",
      "x": "1.100167091",
      "y": "0.746409427"
    },
    {
      "turn": "0",
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      "y": "1.251444746"
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    {
      "turn": "0",
      "x": "1.156007773",
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    {
      "turn": "0",
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    {
      "turn": "0",
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    },
    {
      "turn": "0",
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      "y": "1.763425495"
    },
    {
      "turn": "0",
      "x": "1.296265095",
      "y": "0.949883289"
    },
    {
      "turn": "0",
      "x": "1.362416977",
      "y": "0.689897700"
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    {
      "turn": "0",
      "x": "1.405440219",
      "y": "1.194933019"
    },
    {
      "turn": "0",
      "x": "1.418257659",
      "y": "0.427504110"
    },
    {
      "turn": "0",
      "x": "1.514495241",
      "y": "1.440036222"
    },
    {
      "turn": "0",
      "x": "1.563071948",
      "y": "0.977859723"
    },
    {
      "turn": "0",
      "x": "1.629223830",
      "y": "0.717874134"
    },
    {
      "turn": "0",
      "x": "1.672247072",
      "y": "1.222909453"
    },
    {
      "turn": "0",
      "x": "1.833617568",
      "y": "0.999613070"
    }
  ],
  "radius": "0.134134799"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer

Instance parameters

{
  "n": 33,
  "sides": 5
}

The current leader's answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.325117805",
      "y": "1.350304551"
    },
    {
      "turn": "0",
      "x": "0.325117805",
      "y": "0.994762831"
    },
    {
      "turn": "0",
      "x": "0.325117805",
      "y": "0.726493232"
    },
    {
      "turn": "0",
      "x": "0.424592679",
      "y": "0.477348038"
    },
    {
      "turn": "0",
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      "y": "1.548923536"
    },
    {
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    },
    {
      "turn": "0",
      "x": "0.579528468",
      "y": "0.909652358"
    },
    {
      "turn": "0",
      "x": "0.632654964",
      "y": "0.646695796"
    },
    {
      "turn": "0",
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      "y": "0.387394639"
    },
    {
      "turn": "0",
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    {
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    {
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    {
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    {
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    {
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    {
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    {
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    {
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    }
  ],
  "radius": "0.134134799"
}

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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