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 ```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 ``` ``````prelude: | # The Computer Language Shootout # http://shootout.alioth.debian.org/ # Contributed by Sokolov Yura benchmark: so_spectralnorm: | def eval_A(i,j) return 1.0/((i+j)*(i+j+1)/2+i+1) end def eval_A_times_u(u) v, i = nil, nil (0..u.length-1).collect { |i| v = 0 for j in 0..u.length-1 v += eval_A(i,j)*u[j] end v } end def eval_At_times_u(u) v, i = nil, nil (0..u.length-1).collect{|i| v = 0 for j in 0..u.length-1 v += eval_A(j,i)*u[j] end v } end def eval_AtA_times_u(u) return eval_At_times_u(eval_A_times_u(u)) end n = 500 # ARGV[0].to_i u=[1]*n for i in 1..10 v=eval_AtA_times_u(u) u=eval_AtA_times_u(v) end vBv=0 vv=0 for i in 0..n-1 vBv += u[i]*v[i] vv += v[i]*v[i] end str = "%0.9f" % (Math.sqrt(vBv/vv)), "\n" # print str loop_count: 1 ``````