P87 · Packing and covering · Classic · Hard

Equal discs covering a disc · n = 24

Cover the largest possible disc with n unit-radius discs. Maximise the covered disc radius.

Instancen = 24
ObjectiveMaximize covered disc radius

Record comparison

covered disc radius · Higher is better
RecordValue / intervalAuthor / holderSource
External best known[4.076, 4.077)Jeremy TanErich Friedman ↗
Site recordNo player record yet——

Formal definition

  • ContainerThe editor and certificate normalise the target disc to the closed unit disc centred at (1,1), while public scores are reported in the literature's unit-covering-disc scale.
  • 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.
  • ConstraintsThe n distinct centres lie inside the target disc. Covering discs may overlap and protrude, and their union must cover every point of the target disc.
  • PrecisionInput decimals are parsed as exact rationals, with zero floating-point tolerance in feasibility checks.
  • ObjectiveCovered disc radius R = 1/r, where larger is better.
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.

Source
The current arrangement for Equal discs covering a disc n = 24
LAYOUT & HISTORY

Starter layout

Inspect the layout, solver notes and record history.

Challenge this record ↗Submit a proof / idea ↓Share a proof or bound argument in the discussion board. Accepted contributions earn proof points.
ANSWER FORMAT

How to write your answer

the closed unit disc centred at (1,1)

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": "0.000000000",
      "x": "1.004640496",
      "y": "1.000006265"
    },
    {
      "turn": "0.000000000",
      "x": "1.368866587",
      "y": "0.717927172"
    },
    {
      "turn": "0.000000000",
      "x": "1.452588531",
      "y": "1.020136835"
    },
    {
      "turn": "0.000000000",
      "x": "1.368101994",
      "y": "1.283069840"
    },
    {
      "turn": "0.000000000",
      "x": "0.699147545",
      "y": "0.662881511"
    },
    {
      "turn": "0.000000000",
      "x": "0.698236494",
      "y": "1.336303198"
    },
    {
      "turn": "0.000000000",
      "x": "1.049200415",
      "y": "1.438068226"
    },
    {
      "turn": "0.000000000",
      "x": "0.562801310",
      "y": "0.999408508"
    },
    {
      "turn": "0.000000000",
      "x": "1.050385557",
      "y": "0.562066495"
    },
    {
      "turn": "0.000000000",
      "x": "0.251860387",
      "y": "1.325704887"
    },
    {
      "turn": "0.000000000",
      "x": "0.252744381",
      "y": "0.672272028"
    },
    {
      "turn": "0.000000000",
      "x": "1.831180227",
      "y": "1.179322265"
    },
    {
      "turn": "0.000000000",
      "x": "1.831662393",
      "y": "0.822927410"
    },
    {
      "turn": "0.000000000",
      "x": "1.404570789",
      "y": "0.274010055"
    },
    {
      "turn": "0.000000000",
      "x": "1.402604934",
      "y": "1.727081946"
    },
    {
      "turn": "0.000000000",
      "x": "0.738264145",
      "y": "1.772632137"
    },
    {
      "turn": "0.000000000",
      "x": "0.390053518",
      "y": "1.663604263"
    },
    {
      "turn": "0.000000000",
      "x": "0.391851305",
      "y": "0.334747799"
    },
    {
      "turn": "0.000000000",
      "x": "0.740355660",
      "y": "0.226662495"
    },
    {
      "turn": "0.000000000",
      "x": "0.111861225",
      "y": "0.998798471"
    },
    {
      "turn": "0.000000000",
      "x": "1.695084496",
      "y": "0.478222915"
    },
    {
      "turn": "0.000000000",
      "x": "1.071735063",
      "y": "1.877277575"
    },
    {
      "turn": "0.000000000",
      "x": "1.074108500",
      "y": "0.122919743"
    },
    {
      "turn": "0.000000000",
      "x": "1.693670110",
      "y": "1.523655925"
    }
  ],
  "radius": "0.245301651"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 24,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0.000000000",
      "x": "1.004640496",
      "y": "1.000006265"
    },
    {
      "turn": "0.000000000",
      "x": "1.368866587",
      "y": "0.717927172"
    },
    {
      "turn": "0.000000000",
      "x": "1.452588531",
      "y": "1.020136835"
    },
    {
      "turn": "0.000000000",
      "x": "1.368101994",
      "y": "1.283069840"
    },
    {
      "turn": "0.000000000",
      "x": "0.699147545",
      "y": "0.662881511"
    },
    {
      "turn": "0.000000000",
      "x": "0.698236494",
      "y": "1.336303198"
    },
    {
      "turn": "0.000000000",
      "x": "1.049200415",
      "y": "1.438068226"
    },
    {
      "turn": "0.000000000",
      "x": "0.562801310",
      "y": "0.999408508"
    },
    {
      "turn": "0.000000000",
      "x": "1.050385557",
      "y": "0.562066495"
    },
    {
      "turn": "0.000000000",
      "x": "0.251860387",
      "y": "1.325704887"
    },
    {
      "turn": "0.000000000",
      "x": "0.252744381",
      "y": "0.672272028"
    },
    {
      "turn": "0.000000000",
      "x": "1.831180227",
      "y": "1.179322265"
    },
    {
      "turn": "0.000000000",
      "x": "1.831662393",
      "y": "0.822927410"
    },
    {
      "turn": "0.000000000",
      "x": "1.404570789",
      "y": "0.274010055"
    },
    {
      "turn": "0.000000000",
      "x": "1.402604934",
      "y": "1.727081946"
    },
    {
      "turn": "0.000000000",
      "x": "0.738264145",
      "y": "1.772632137"
    },
    {
      "turn": "0.000000000",
      "x": "0.390053518",
      "y": "1.663604263"
    },
    {
      "turn": "0.000000000",
      "x": "0.391851305",
      "y": "0.334747799"
    },
    {
      "turn": "0.000000000",
      "x": "0.740355660",
      "y": "0.226662495"
    },
    {
      "turn": "0.000000000",
      "x": "0.111861225",
      "y": "0.998798471"
    },
    {
      "turn": "0.000000000",
      "x": "1.695084496",
      "y": "0.478222915"
    },
    {
      "turn": "0.000000000",
      "x": "1.071735063",
      "y": "1.877277575"
    },
    {
      "turn": "0.000000000",
      "x": "1.074108500",
      "y": "0.122919743"
    },
    {
      "turn": "0.000000000",
      "x": "1.693670110",
      "y": "1.523655925"
    }
  ],
  "radius": "0.245301651"
}

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

Discuss strategies, share construction methods, or ask questions. Any signed-in user can post under their public byline and unique #UID. New posts appear after moderation.

No threads yet. Start the first discussion.