41 lines
905 B
Nim
41 lines
905 B
Nim
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import math, random, sequtils, stats, strformat, strutils
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proc drawHistogram(ns: seq[float]) =
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# Distribute values in bins.
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const NBins = 50
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var minval = min(ns)
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var maxval = max(ns)
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var h = newSeq[int](NBins + 1)
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for n in ns:
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let pos = ((n - minval) * NBins / (maxval - minval)).toInt
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inc h[pos]
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# Eliminate extremes values.
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const MaxWidth = 50
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let mx = max(h)
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var first = 0
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while (h[first] / mx * MaxWidth).toInt == 0: inc first
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var last = h.high
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while (h[last] / mx * MaxWidth).toInt == 0: dec last
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# Draw the histogram.
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echo ""
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for n in first..last:
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echo repeat('+', (h[n] / mx * MaxWidth).toInt)
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echo ""
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const N = 100_000
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randomize()
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let u1, u2 = newSeqWith(N, rand(1.0))
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var z = newSeq[float](N)
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for i in 0..<N:
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z[i] = sqrt(-2 * ln(u1[i])) * cos(2 * PI * u2[i])
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echo &"μ = {z.mean:.12f} σ = {z.standardDeviation:.12f}"
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z.drawHistogram()
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