gistfile1.rb

require 'gr/plot'

srand(1234)
res = []
500.times.each do |i|
  res << rand(10000)
end

x_res = []
y_res = []
z_res = []
res.each_cons(3) do |x, y, z|
  x_res << x
  y_res << y
  z_res << z
end
GR.scatter3(x_res, y_res, z_res, title: "spectral test")
GR.savefig("figure1.jpg")

R_A = 137
R_C = 187
R_M = 256
R_SEED = 1234
r = R_SEED
res2 = []
500.times.each do |i|
  new_r = (R_A * r + R_C) % R_M
  res2 << new_r
  r = new_r
end
x2_res = []
y2_res = []
z2_res = []
res2.each_cons(3) do |x, y, z|
  x2_res << x
  y2_res << y
  z2_res << z
end
GR.scatter3(x2_res, y2_res, z2_res, title: "LCG spectral test")
GR.savefig("figure2.jpg")