P87 · Packing and covering · Classic

Equal discs covering a disc · n = 17

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

Instancen = 17
ObjectiveMaximize covered disc radius

Record comparison

covered disc radius · Higher is better
RecordValue / intervalAuthor / holderSource
Proven optimum[3.349729261451910954711870735939, 3.349729261451910954711870735940]VonEquinoxDiskCoveringSolve ↗
Site recordNo player record yet——

The continuous optimum is proved, so competition submissions are closed. Historical records and contribution points are retained. Because finite-decimal coordinates cannot attain this value exactly, the current certificate is not claimed optimal on the nine-decimal grid.

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.
Inspect in 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 = 17
LAYOUT & HISTORY

Starter layout

Inspect the layout, solver notes and record history.

Proven optimumSubmit 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": "0.737111109",
      "y": "1.187633634"
    },
    {
      "turn": "0.000000000",
      "x": "0.734942002",
      "y": "0.815443203"
    },
    {
      "turn": "0.000000000",
      "x": "1.267976840",
      "y": "0.998438241"
    },
    {
      "turn": "0.000000000",
      "x": "1.114946894",
      "y": "1.403379291"
    },
    {
      "turn": "0.000000000",
      "x": "1.110237504",
      "y": "0.595308332"
    },
    {
      "turn": "0.000000000",
      "x": "0.608821804",
      "y": "1.679283883"
    },
    {
      "turn": "0.000000000",
      "x": "0.600930977",
      "y": "0.325321640"
    },
    {
      "turn": "0.000000000",
      "x": "1.673718719",
      "y": "1.344736246"
    },
    {
      "turn": "0.000000000",
      "x": "1.669654885",
      "y": "0.647434643"
    },
    {
      "turn": "0.000000000",
      "x": "1.004947314",
      "y": "1.888764566"
    },
    {
      "turn": "0.000000000",
      "x": "0.994587976",
      "y": "0.111238138"
    },
    {
      "turn": "0.000000000",
      "x": "0.209492350",
      "y": "1.004607040"
    },
    {
      "turn": "0.000000000",
      "x": "1.846987813",
      "y": "0.995063803"
    },
    {
      "turn": "0.000000000",
      "x": "0.259215756",
      "y": "1.434442312"
    },
    {
      "turn": "0.000000000",
      "x": "1.503065826",
      "y": "0.245139481"
    },
    {
      "turn": "0.000000000",
      "x": "0.254202431",
      "y": "0.574221416"
    },
    {
      "turn": "0.000000000",
      "x": "1.511829926",
      "y": "1.748945747"
    }
  ],
  "radius": "0.298531590"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 17,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0.000000000",
      "x": "0.737111109",
      "y": "1.187633634"
    },
    {
      "turn": "0.000000000",
      "x": "0.734942002",
      "y": "0.815443203"
    },
    {
      "turn": "0.000000000",
      "x": "1.267976840",
      "y": "0.998438241"
    },
    {
      "turn": "0.000000000",
      "x": "1.114946894",
      "y": "1.403379291"
    },
    {
      "turn": "0.000000000",
      "x": "1.110237504",
      "y": "0.595308332"
    },
    {
      "turn": "0.000000000",
      "x": "0.608821804",
      "y": "1.679283883"
    },
    {
      "turn": "0.000000000",
      "x": "0.600930977",
      "y": "0.325321640"
    },
    {
      "turn": "0.000000000",
      "x": "1.673718719",
      "y": "1.344736246"
    },
    {
      "turn": "0.000000000",
      "x": "1.669654885",
      "y": "0.647434643"
    },
    {
      "turn": "0.000000000",
      "x": "1.004947314",
      "y": "1.888764566"
    },
    {
      "turn": "0.000000000",
      "x": "0.994587976",
      "y": "0.111238138"
    },
    {
      "turn": "0.000000000",
      "x": "0.209492350",
      "y": "1.004607040"
    },
    {
      "turn": "0.000000000",
      "x": "1.846987813",
      "y": "0.995063803"
    },
    {
      "turn": "0.000000000",
      "x": "0.259215756",
      "y": "1.434442312"
    },
    {
      "turn": "0.000000000",
      "x": "1.503065826",
      "y": "0.245139481"
    },
    {
      "turn": "0.000000000",
      "x": "0.254202431",
      "y": "0.574221416"
    },
    {
      "turn": "0.000000000",
      "x": "1.511829926",
      "y": "1.748945747"
    }
  ],
  "radius": "0.298531590"
}

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.