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[Ruby] 루비에서 그래프 구현하기 (gnuplot 설치)

풀이

gnuplot가 설치가 되었다면 간단하게 sin그래프를 구현해보았습니다.
x변수에 [-5.0, -4.9, -4.8, ... 4.8, 4.9, 5.0]리스트를 생성하고 y변수에는 x 리스트에 값들의 sin값을 구한 값의 리스트를 넣어 주어서 그래프를 그려보았습니다. 정확한 값을 위해 0.1씩 증가할때 round로 소수점 1자리까지 나오게 하였는데요.
특정 구간에서 -3.5999999999999996와 다들 이시는 컴퓨터 저장 방식에 따른 부동소수점의 문제가 발생하기 때문에 정확한 값을 저장하기 위해서 반올림을 하였습니다.

round 미사용

x = (-5..5).step(0.1).collect { |v| v.to_f }
puts x.join(" ")

출력

-5.0 -4.9 -4.8 -4.7 -4.6 -4.5 -4.4 -4.3 -4.2 -4.1 -4.0 -3.9 -3.8 -3.7 -3.5999999999999996 -3.5 -3.4 -3.3 -3.2 -3.0999999999999996 -3.0 -2.9 -2.8 -2.6999999999999997 -2.5999999999999996 -2.5 -2.4 -2.3 -2.1999999999999997 -2.0999999999999996 -2.0 -1.9 -1.7999999999999998 -1.6999999999999997 -1.5999999999999996 -1.5 -1.4 -1.2999999999999998 -1.1999999999999997 -1.0999999999999996 -1.0 -0.8999999999999995 -0.7999999999999998 -0.7000000000000002 -0.5999999999999996 -0.5 -0.39999999999999947 -0.2999999999999998 -0.1999999999999993 -0.09999999999999964 0.0 0.10000000000000053 0.20000000000000018 0.3000000000000007 0.40000000000000036 0.5 0.6000000000000005 0.7000000000000002 0.8000000000000007 0.9000000000000004 1.0 1.1000000000000005 1.2000000000000002 1.3000000000000007 1.4000000000000004 1.5 1.6000000000000005 1.7000000000000002 1.8000000000000007 1.9000000000000004 2.0 2.1000000000000005 2.2 2.3000000000000007 2.4000000000000004 2.5 2.6000000000000005 2.7 2.8000000000000007 2.9000000000000004 3.0 3.0999999999999996 3.200000000000001 3.3000000000000007 3.4000000000000004 3.5 3.5999999999999996 3.700000000000001 3.8000000000000007 3.9000000000000004 4.0 4.1 4.200000000000001 4.300000000000001 4.4 4.5 4.600000000000001 4.700000000000001 4.800000000000001 4.9 5.0

round 사용

x = (-5..5).step(0.1).collect { |v| v.to_f.round(1) }
puts x.join(" ")

출력

-5.0 -4.9 -4.8 -4.7 -4.6 -4.5 -4.4 -4.3 -4.2 -4.1 -4.0 -3.9 -3.8 -3.7 -3.6 -3.5 -3.4 -3.3 -3.2 -3.1 -3.0 -2.9 -2.8 -2.7 -2.6 -2.5 -2.4 -2.3 -2.2 -2.1 -2.0 -1.9 -1.8 -1.7 -1.6 -1.5 -1.4 -1.3 -1.2 -1.1 -1.0 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5.0

코드

require 'gnuplot'

Gnuplot.open do |g|
  Gnuplot::Plot.new(g) do |plot|
    x = (-5..5).step(0.1).collect { |v| v.to_f.round 1 }
    y = x.collect { |v| Math.sin v }

    plot.data << Gnuplot::DataSet.new([x, y]) do |d|
      d.with = "lines"
      d.linewidth = 2
    end
  end
end

출력