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Roulette Wheel
a = [1,7,3]
makeWheel = (a) => {
const sum = d3.sum(a)
return a.map(d => {
return {value:d, prob:d/sum}
})
}
wheel = makeWheel(a)
spinWheel = (wheel) => {
const probs = wheel.map(slice => slice.prob)
const cprobs = d3.cumsum(probs)
const r = d3.randomUniform(0,1)()
return [...cprobs,r].sort((a,b) => a - b).indexOf(r)
}
results = {
const results = []
for(let i = 0;i < 10000; i = i + 1){
const index = spinWheel(wheel)
results.push(wheel[index].value)
}
return results
}
d3.bin()(results).map(a => a.length/10000)
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