P82 · Packing and covering · Classic · Hard

Equal circles in regular polygons · m = 5 · n = 38

Pack n equal circles into the regular m-gon with centre (1,1), circumradius 1, and first vertex (2,1) so as to maximise their common radius.

Instancem = 5 · n = 38
ObjectiveMaximize circle radius

Record comparison

circle radius · Higher is better
RecordValue / intervalAuthor / holderSource
External best known[0.125056798043, 0.125056798045]Paolo AmorePackomania ↗
Site recordNo player record yet——

Formal definition

  • ContainerThe editor and certificate normalise the container to the exact regular m-gon with centre (1,1), circumradius 1, and first vertex (2,1), while public scores follow the literature convention. Boundary contact is allowed.
  • SubmissionSubmit {radius, placements:[{x,y,turn},…]}, with each value written as a decimal string of at most nine places. Here x, y are centre coordinates; circles require turn = 0 and polygons use turn = tan(θ/2). Coordinates and turn must lie in [−4, 4], with 0 < radius ≤ 4.
  • ConstraintsExactly n congruent pieces lie wholly inside the container with pairwise disjoint interiors. Polygons may rotate independently by arbitrary angles.
  • PrecisionInput decimals are parsed as exact rationals and regular-polygon vertices are defined algebraically, with zero floating-point tolerance in feasibility checks.
  • ObjectiveMaximise the circle radius r (with container circumradius fixed at 1).
Open full editor ↗

Layout shown: starter layout

VERIFIED CONSTRUCTIONVERIFIED CONSTRUCTION

Getting a feel for it

Literature targets and coordinate certificates

Literature targets are converted at their published precision, while nine-decimal coordinate certificates are stored and displayed alongside the source values. Pentagon and hexagon rows n = 41–100 and octagon rows n = 41–48 cite Packomania's value and author without importing its coordinates; they start from an ordinary site grid baseline.

Source
The current arrangement for Equal circles in regular polygons m = 5 · n = 38
LAYOUT & HISTORY

Starter layout

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ANSWER FORMAT

How to write your answer

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

Submit {radius, placements:[{x,y,turn},…]}, with each value written as a decimal string of at most nine places. Here x, y are centre coordinates; circles require turn = 0 and polygons use turn = tan(θ/2). Coordinates and turn must lie in [−4, 4], with 0 < radius ≤ 4.

Starter answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.316039804",
      "y": "1.495603308"
    },
    {
      "turn": "0",
      "x": "0.316039804",
      "y": "1.245489712"
    },
    {
      "turn": "0",
      "x": "0.316039804",
      "y": "0.995376115"
    },
    {
      "turn": "0",
      "x": "0.316039804",
      "y": "0.745262519"
    },
    {
      "turn": "0",
      "x": "0.337572239",
      "y": "0.496077517"
    },
    {
      "turn": "0",
      "x": "0.553520180",
      "y": "1.574088222"
    },
    {
      "turn": "0",
      "x": "0.553771886",
      "y": "1.323208872"
    },
    {
      "turn": "0",
      "x": "0.553771886",
      "y": "1.073095276"
    },
    {
      "turn": "0",
      "x": "0.565989823",
      "y": "0.754306791"
    },
    {
      "turn": "0",
      "x": "0.587577305",
      "y": "0.503444892"
    },
    {
      "turn": "0",
      "x": "0.752386781",
      "y": "0.921079045"
    },
    {
      "turn": "0",
      "x": "0.770029110",
      "y": "1.448865643"
    },
    {
      "turn": "0",
      "x": "0.770376614",
      "y": "1.198152074"
    },
    {
      "turn": "0",
      "x": "0.785505217",
      "y": "0.350535270"
    },
    {
      "turn": "0",
      "x": "0.792106692",
      "y": "0.647405096"
    },
    {
      "turn": "0",
      "x": "0.871584528",
      "y": "1.677433593"
    },
    {
      "turn": "0",
      "x": "0.968991509",
      "y": "1.046135843"
    },
    {
      "turn": "0",
      "x": "0.986633838",
      "y": "1.323808845"
    },
    {
      "turn": "0",
      "x": "0.992457896",
      "y": "0.797125523"
    },
    {
      "turn": "0",
      "x": "1.009057260",
      "y": "0.522949233"
    },
    {
      "turn": "0",
      "x": "1.023377383",
      "y": "0.273245919"
    },
    {
      "turn": "0",
      "x": "1.088189257",
      "y": "1.552376795"
    },
    {
      "turn": "0",
      "x": "1.185248733",
      "y": "1.171792614"
    },
    {
      "turn": "0",
      "x": "1.189919621",
      "y": "1.780866935"
    },
    {
      "turn": "0",
      "x": "1.208715120",
      "y": "0.922782294"
    },
    {
      "turn": "0",
      "x": "1.209408464",
      "y": "0.672669659"
    },
    {
      "turn": "0",
      "x": "1.261249548",
      "y": "0.195956567"
    },
    {
      "turn": "0",
      "x": "1.286804152",
      "y": "1.400360565"
    },
    {
      "turn": "0",
      "x": "1.306123244",
      "y": "0.442011769"
    },
    {
      "turn": "0",
      "x": "1.388534516",
      "y": "1.628850704"
    },
    {
      "turn": "0",
      "x": "1.425665688",
      "y": "0.798326430"
    },
    {
      "turn": "0",
      "x": "1.433992181",
      "y": "1.197936604"
    },
    {
      "turn": "0",
      "x": "1.526268912",
      "y": "0.560724429"
    },
    {
      "turn": "0",
      "x": "1.535547599",
      "y": "1.426504555"
    },
    {
      "turn": "0",
      "x": "1.580850319",
      "y": "0.995477971"
    },
    {
      "turn": "0",
      "x": "1.673281996",
      "y": "0.763070578"
    },
    {
      "turn": "0",
      "x": "1.682755570",
      "y": "1.223890166"
    },
    {
      "turn": "0",
      "x": "1.843794705",
      "y": "1.000092391"
    }
  ],
  "radius": "0.125056797"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 38,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.316039804",
      "y": "1.495603308"
    },
    {
      "turn": "0",
      "x": "0.316039804",
      "y": "1.245489712"
    },
    {
      "turn": "0",
      "x": "0.316039804",
      "y": "0.995376115"
    },
    {
      "turn": "0",
      "x": "0.316039804",
      "y": "0.745262519"
    },
    {
      "turn": "0",
      "x": "0.337572239",
      "y": "0.496077517"
    },
    {
      "turn": "0",
      "x": "0.553520180",
      "y": "1.574088222"
    },
    {
      "turn": "0",
      "x": "0.553771886",
      "y": "1.323208872"
    },
    {
      "turn": "0",
      "x": "0.553771886",
      "y": "1.073095276"
    },
    {
      "turn": "0",
      "x": "0.565989823",
      "y": "0.754306791"
    },
    {
      "turn": "0",
      "x": "0.587577305",
      "y": "0.503444892"
    },
    {
      "turn": "0",
      "x": "0.752386781",
      "y": "0.921079045"
    },
    {
      "turn": "0",
      "x": "0.770029110",
      "y": "1.448865643"
    },
    {
      "turn": "0",
      "x": "0.770376614",
      "y": "1.198152074"
    },
    {
      "turn": "0",
      "x": "0.785505217",
      "y": "0.350535270"
    },
    {
      "turn": "0",
      "x": "0.792106692",
      "y": "0.647405096"
    },
    {
      "turn": "0",
      "x": "0.871584528",
      "y": "1.677433593"
    },
    {
      "turn": "0",
      "x": "0.968991509",
      "y": "1.046135843"
    },
    {
      "turn": "0",
      "x": "0.986633838",
      "y": "1.323808845"
    },
    {
      "turn": "0",
      "x": "0.992457896",
      "y": "0.797125523"
    },
    {
      "turn": "0",
      "x": "1.009057260",
      "y": "0.522949233"
    },
    {
      "turn": "0",
      "x": "1.023377383",
      "y": "0.273245919"
    },
    {
      "turn": "0",
      "x": "1.088189257",
      "y": "1.552376795"
    },
    {
      "turn": "0",
      "x": "1.185248733",
      "y": "1.171792614"
    },
    {
      "turn": "0",
      "x": "1.189919621",
      "y": "1.780866935"
    },
    {
      "turn": "0",
      "x": "1.208715120",
      "y": "0.922782294"
    },
    {
      "turn": "0",
      "x": "1.209408464",
      "y": "0.672669659"
    },
    {
      "turn": "0",
      "x": "1.261249548",
      "y": "0.195956567"
    },
    {
      "turn": "0",
      "x": "1.286804152",
      "y": "1.400360565"
    },
    {
      "turn": "0",
      "x": "1.306123244",
      "y": "0.442011769"
    },
    {
      "turn": "0",
      "x": "1.388534516",
      "y": "1.628850704"
    },
    {
      "turn": "0",
      "x": "1.425665688",
      "y": "0.798326430"
    },
    {
      "turn": "0",
      "x": "1.433992181",
      "y": "1.197936604"
    },
    {
      "turn": "0",
      "x": "1.526268912",
      "y": "0.560724429"
    },
    {
      "turn": "0",
      "x": "1.535547599",
      "y": "1.426504555"
    },
    {
      "turn": "0",
      "x": "1.580850319",
      "y": "0.995477971"
    },
    {
      "turn": "0",
      "x": "1.673281996",
      "y": "0.763070578"
    },
    {
      "turn": "0",
      "x": "1.682755570",
      "y": "1.223890166"
    },
    {
      "turn": "0",
      "x": "1.843794705",
      "y": "1.000092391"
    }
  ],
  "radius": "0.125056797"
}

Submit {radius, placements:[{x,y,turn},…]}, with each value written as a decimal string of at most nine places. Here x, y are centre coordinates; circles require turn = 0 and polygons use turn = tan(θ/2). Coordinates and turn must lie in [−4, 4], with 0 < radius ≤ 4. · Verifier v1.0.0

DISCUSSION

Discussion

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