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Preferential Attachment
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# AgentBase is Free Software, available under GPL v3 or any later version. | |
# Original AgentScript code @ 2013, 2014 Owen Densmore and RedfishGroup LLC. | |
# AgentBase (c) 2014, Wybo Wiersma. | |
# Preferential Attachment models a dynamic graph where new links | |
# preferentially attach to the nodes that have the most links. This | |
# results in a power-law distribution. | |
u = ABM.util | |
class ABM.PreferentialAttachmentModel extends ABM.Model | |
setup: -> | |
@refreshPatches = false # for static patches | |
# globals | |
@circleLayout = true | |
@histogram = [] | |
@stopTick = 400 | |
# defaults | |
@agents.setDefault "shape", "circle" | |
@links.setDefault "thickness", .75 # Easier to see thiner link | |
@patches.create() | |
@agents.create 1 | |
@makeNode @agents[0] | |
step: -> | |
@makeNode @findPartner() | |
for agent in @agents | |
agent.size = Math.sqrt agent.linkNeighbors().length | |
@agents.formCircle @patches.max.x * 0.9 | |
@histogram = @agents.histogram 1, (agent) -> | |
agent.linkNeighbors().length | |
if @animator.ticks % 25 is 0 | |
console.log "Tick: #{@animator.ticks} Histogram: [#{@histogram}]" | |
if @animator.ticks is @stopTick | |
(console.log "Stopping at stopTick: #{@animator.ticks}"; @stop()) | |
makeNode: (toNode) -> | |
@agents.create 1, (agent) => | |
@links.create agent, toNode | |
agent.moveTo toNode.position | |
agent.forward 8 | |
findPartner: -> | |
@links.sample().bothEnds().sample() | |
window.model = new ABM.PreferentialAttachmentModel { | |
div: "world", | |
patchSize: 5, | |
mapSize: 90 | |
} | |
window.model.start() | |
# Uses the AgentBase library (03-02-2017 release) | |
# https://github.com/wybo/agentbase/commit/3501302567c018da82601cd858be2ea6d0b9c74d |
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