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32 lines
774 B
Ruby
32 lines
774 B
Ruby
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n = 2_500_000 # (ARGV.shift || 1).to_i
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alt = 1.0 ; s0 = s1 = s2 = s3 = s4 = s5 = s6 = s7 = s8 = 0.0
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1.upto(n) do |d|
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d = d.to_f ; d2 = d * d ; d3 = d2 * d ; ds = Math.sin(d) ; dc = Math.cos(d)
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s0 += (2.0 / 3.0) ** (d - 1.0)
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s1 += 1.0 / Math.sqrt(d)
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s2 += 1.0 / (d * (d + 1.0))
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s3 += 1.0 / (d3 * ds * ds)
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s4 += 1.0 / (d3 * dc * dc)
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s5 += 1.0 / d
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s6 += 1.0 / d2
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s7 += alt / d
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s8 += alt / (2.0 * d - 1.0)
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alt = -alt
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end
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if false
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printf("%.9f\t(2/3)^k\n", s0)
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printf("%.9f\tk^-0.5\n", s1)
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printf("%.9f\t1/k(k+1)\n", s2)
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printf("%.9f\tFlint Hills\n", s3)
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printf("%.9f\tCookson Hills\n", s4)
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printf("%.9f\tHarmonic\n", s5)
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printf("%.9f\tRiemann Zeta\n", s6)
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printf("%.9f\tAlternating Harmonic\n", s7)
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printf("%.9f\tGregory\n", s8)
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end
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