33 lines
836 B
Nim
33 lines
836 B
Nim
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import random, sequtils, stats, strutils, strformat
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proc drawHistogram(ns: seq[float]) =
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var h = newSeq[int](11)
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for n in ns:
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let pos = (n * 10).toInt
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inc h[pos]
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const maxWidth = 50
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let mx = max(h)
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echo ""
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for n, count in h:
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echo n.toFloat / 10, ": ", repeat('+', int(count / mx * maxWidth))
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echo ""
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randomize()
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# First part: compute directly from a sequence of values.
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echo "For 100 numbers:"
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let ns = newSeqWith(100, rand(1.0))
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echo &"μ = {ns.mean:.12f} σ = {ns.standardDeviation:.12f}"
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ns.drawHistogram()
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# Second part: compute incrementally using "RunningStat".
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for count in [1_000, 10_000, 100_000, 1_000_000]:
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echo &"For {count} numbers:"
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var rs: RunningStat
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for _ in 1..count:
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let n = rand(1.0)
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rs.push(n)
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echo &"μ = {rs.mean:.12f} σ = {rs.standardDeviation:.12f}"
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echo()
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