28 lines
677 B
Julia
28 lines
677 B
Julia
function questionmark(x)
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y, p = fldmod(x, 1)
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q, d = 1 - p, .5
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while y + d > y
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p < q ? (q -= p) : (p -= q; y += d)
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d /= 2
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end
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y
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end
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function questionmark_inv(x)
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y, bits = fldmod(x, 1)
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lo, hi = [0, 1], [1, 1]
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while bits ≉ 0
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bits, bit = modf(2bits)
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bit ≥ 1 ? (lo .+= hi) : (hi .+= lo)
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end
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y + /(lo...)
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end
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x, y = 0.7182818281828, 0.1213141516171819
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for (a, b) ∈ [
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(5/3, questionmark((1 + √5)/2)),
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((√13-7)/6, questionmark_inv(-5/9)),
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(x, questionmark_inv(questionmark(x))),
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(y, questionmark(questionmark_inv(y)))]
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println(a, a ≈ b ? " ≈ " : " != ", b)
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end
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