P82 · Packing and covering · Classic · Hard

Equal circles in regular polygons · m = 5 · n = 22

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 = 22
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 = 22, 0.161673301
Current leader

0.161673301

circle radius

Answer sourcePaolo Amore
Solution methodPublished reference construction
Challenge this record Submit a proof / idea Share a proof or idea in the discussion. Accepted contributions can earn proof points.
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": "0.352656307",
      "y": "1.398689488"
    },
    {
      "turn": "0",
      "x": "0.352656307",
      "y": "1.028940276"
    },
    {
      "turn": "0",
      "x": "0.352656307",
      "y": "0.601310512"
    },
    {
      "turn": "0",
      "x": "0.595218098",
      "y": "0.815125394"
    },
    {
      "turn": "0",
      "x": "0.617938056",
      "y": "1.213814882"
    },
    {
      "turn": "0",
      "x": "0.632221499",
      "y": "1.561158960"
    },
    {
      "turn": "0",
      "x": "0.632221499",
      "y": "0.438841040"
    },
    {
      "turn": "0",
      "x": "0.860499847",
      "y": "1.000000000"
    },
    {
      "turn": "0",
      "x": "0.876740173",
      "y": "0.656070851"
    },
    {
      "turn": "0",
      "x": "0.916241453",
      "y": "1.338587111"
    },
    {
      "turn": "0",
      "x": "0.939742394",
      "y": "1.661078556"
    },
    {
      "turn": "0",
      "x": "0.939742394",
      "y": "0.338921444"
    },
    {
      "turn": "0",
      "x": "1.158803244",
      "y": "1.124772229"
    },
    {
      "turn": "0",
      "x": "1.165538743",
      "y": "0.801495786"
    },
    {
      "turn": "0",
      "x": "1.240104919",
      "y": "1.437730795"
    },
    {
      "turn": "0",
      "x": "1.247263288",
      "y": "1.760998151"
    },
    {
      "turn": "0",
      "x": "1.247263288",
      "y": "0.239001849"
    },
    {
      "turn": "0",
      "x": "1.359017448",
      "y": "0.542422405"
    },
    {
      "turn": "0",
      "x": "1.468460828",
      "y": "1.031685136"
    },
    {
      "turn": "0",
      "x": "1.549762503",
      "y": "1.344643702"
    },
    {
      "turn": "0",
      "x": "1.613053610",
      "y": "0.742469035"
    },
    {
      "turn": "0",
      "x": "1.791225710",
      "y": "1.012298109"
    }
  ],
  "radius": "0.161673301"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer

Instance parameters

{
  "n": 22,
  "sides": 5
}

The current leader's answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.352656307",
      "y": "1.398689488"
    },
    {
      "turn": "0",
      "x": "0.352656307",
      "y": "1.028940276"
    },
    {
      "turn": "0",
      "x": "0.352656307",
      "y": "0.601310512"
    },
    {
      "turn": "0",
      "x": "0.595218098",
      "y": "0.815125394"
    },
    {
      "turn": "0",
      "x": "0.617938056",
      "y": "1.213814882"
    },
    {
      "turn": "0",
      "x": "0.632221499",
      "y": "1.561158960"
    },
    {
      "turn": "0",
      "x": "0.632221499",
      "y": "0.438841040"
    },
    {
      "turn": "0",
      "x": "0.860499847",
      "y": "1.000000000"
    },
    {
      "turn": "0",
      "x": "0.876740173",
      "y": "0.656070851"
    },
    {
      "turn": "0",
      "x": "0.916241453",
      "y": "1.338587111"
    },
    {
      "turn": "0",
      "x": "0.939742394",
      "y": "1.661078556"
    },
    {
      "turn": "0",
      "x": "0.939742394",
      "y": "0.338921444"
    },
    {
      "turn": "0",
      "x": "1.158803244",
      "y": "1.124772229"
    },
    {
      "turn": "0",
      "x": "1.165538743",
      "y": "0.801495786"
    },
    {
      "turn": "0",
      "x": "1.240104919",
      "y": "1.437730795"
    },
    {
      "turn": "0",
      "x": "1.247263288",
      "y": "1.760998151"
    },
    {
      "turn": "0",
      "x": "1.247263288",
      "y": "0.239001849"
    },
    {
      "turn": "0",
      "x": "1.359017448",
      "y": "0.542422405"
    },
    {
      "turn": "0",
      "x": "1.468460828",
      "y": "1.031685136"
    },
    {
      "turn": "0",
      "x": "1.549762503",
      "y": "1.344643702"
    },
    {
      "turn": "0",
      "x": "1.613053610",
      "y": "0.742469035"
    },
    {
      "turn": "0",
      "x": "1.791225710",
      "y": "1.012298109"
    }
  ],
  "radius": "0.161673301"
}

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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