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August 29, 2015 13:57
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Simulation demonstrating the characteristics of the Secretary Problem (https://en.wikipedia.org/wiki/Secretary_problem) using Julia (http://julialang.org/).
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# Do K simulation runs each with N items. The goal is to find the largest | |
# item in the list, without "remembering" and carrying along some previous | |
# maximum. | |
N = 10000 | |
K = 1000 | |
diffs = zeros(Int, K) | |
pct_diffs = zeros(Float64, K) | |
for i = 1:K | |
scores = randn(N) * 100 |> int |> abs | |
max_score = maximum(scores) | |
drop_count = N / e |> round |> int | |
max_dropped = maximum(scores[1:drop_count]) | |
max_chosen = minimum(scores) | |
for v = scores[drop_count+1:end] | |
max_chosen = v | |
if v > max_dropped | |
break | |
end | |
end | |
diffs[i] = max_score - max_chosen | |
pct_diffs[i] = (max_score - max_chosen) / max_score | |
end | |
pct_correct = count(x -> x == 0, diffs) / K | |
mean_error = mean(pct_diffs) | |
println("% correct: ", pct_correct) | |
println("mean % error: ", mean_error) |
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