# hashtables in Ruby
require "benchmark"

maxiter = 10000000

ht = Hash.new
durationMeas = []
durationSum = 0.0
10.step(1,-1) do |n|
    duration = Benchmark.realtime do
      ht.clear
      maxiter.step(1,-1) {|i| ht[i] = Float(i+n)}
    end
    durationSum = durationSum + duration
    durationMeas.push duration
    puts n
end
adjustment = Benchmark.realtime do
    maxiter.step(1,-1) {|i| Float(i+3)}
end

mean = durationSum/10.0
stdv = Math.sqrt(durationMeas.inject(0.0) {|var, m| var + (m-mean)**2}/10.0)
printf("insert time (ordered) in seconds: mean %.3f, adj-mean %.3f, stdv %.3f\n", mean, mean-adjustment,stdv)

Accum = Struct.new(:lfsr, :x)

duration = Benchmark.realtime do
    (1..maxiter).inject(Accum.new(1,0.0)) { |a,i| nlfsr = (a.lfsr >> 1) ^ (0 - (a.lfsr & 1) & 0xd0000001); val = ht[nlfsr]; nx = a.x + (val.nil? ? 0 : val); a.lfsr = nlfsr; a.x = nx; a }
end
adjustment = Benchmark.realtime do
    (1..maxiter).inject(Accum.new(1,0.0)) { |a,i| nlfsr = (a.lfsr >> 1) ^ (0 - (a.lfsr & 1) & 0xd0000001); val = 0; nx = a.x + (val.nil? ? 0 : val); a.lfsr = nlfsr; a.x = nx; a }
end
printf("lookup timing (mostly misses) in seconds: %.3f, adj %.3f\n", duration, duration-adjustment)

durationMeas = []
durationSum = 0.0
10.step(1,-1) do |n|
    duration = Benchmark.realtime do
      ht.clear
      (1..maxiter).inject(1) { |lfsr,i| nlfsr = (lfsr >> 1) ^ (0 - (lfsr & 1) & 0xd0000001); ht[nlfsr] = Float(i+n); nlfsr; }
    end
    durationSum = durationSum + duration
    durationMeas.push duration
    puts n
end
adjustment = Benchmark.realtime do
    (1..maxiter).inject(1) { |lfsr,i| nlfsr = (lfsr >> 1) ^ (0 - (lfsr & 1) & 0xd0000001); Float(i+3); nlfsr; }
end

mean = durationSum/10.0
stdv = Math.sqrt(durationMeas.inject(0.0) {|var, m| var + (m-mean)**2}/10.0)
printf("insert time (unordered) in seconds: mean %.3f, adj-mean %.3f, stdv %.3f\n", mean, mean-adjustment, stdv)

duration = Benchmark.realtime do
    (1..maxiter).inject(Accum.new(1,0.0)) { |a,i| nlfsr = (a.lfsr >> 1) ^ (0 - (a.lfsr & 1) & 0xd0000001); val = ht[nlfsr]; nx = a.x + (val.nil? ? 0 : val); a.lfsr = nlfsr; a.x = nx; a }
end
adjustment = Benchmark.realtime do
    (1..maxiter).inject(Accum.new(1,0.0)) { |a,i| nlfsr = (a.lfsr >> 1) ^ (0 - (a.lfsr & 1) & 0xd0000001); val = 0; nx = a.x + (val.nil? ? 0 : val); a.lfsr = nlfsr; a.x = nx; a }
end
printf("lookup timing (no misses) in seconds: %.3f, adj %.3f\n", duration, duration-adjustment);