зеркало из https://github.com/github/ruby.git
51 строка
870 B
Ruby
51 строка
870 B
Ruby
# The Computer Language Shootout
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# http://shootout.alioth.debian.org/
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# Contributed by Sokolov Yura
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def eval_A(i,j)
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return 1.0/((i+j)*(i+j+1)/2+i+1)
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end
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def eval_A_times_u(u)
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v, i = nil, nil
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(0..u.length-1).collect { |i|
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v = 0
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for j in 0..u.length-1
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v += eval_A(i,j)*u[j]
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end
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v
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}
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end
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def eval_At_times_u(u)
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v, i = nil, nil
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(0..u.length-1).collect{|i|
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v = 0
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for j in 0..u.length-1
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v += eval_A(j,i)*u[j]
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end
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v
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}
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end
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def eval_AtA_times_u(u)
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return eval_At_times_u(eval_A_times_u(u))
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end
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n = 500 # ARGV[0].to_i
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u=[1]*n
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for i in 1..10
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v=eval_AtA_times_u(u)
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u=eval_AtA_times_u(v)
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end
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vBv=0
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vv=0
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for i in 0..n-1
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vBv += u[i]*v[i]
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vv += v[i]*v[i]
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end
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str = "%0.9f" % (Math.sqrt(vBv/vv)), "\n"
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# print str
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