hofstadter_female_differences.lua

gistfile1.lua

f = {[0] = 1}
m = {[0] = 0}

len = 100000000

for i = 1, len do
   m[i] = i - f[m[i-1]]
   f[i] = i - m[f[i-1]]
end

df, dm = {}, {}

for i = 1, len do
   df[i], dm[i] = f[i] - f[i-1], m[i] - m[i-1]
end

function cond_a(t, n)
   return t[n] == 1 and t[n-1] == 1 and t[n-2] == 0 and t[n-3] == 1 and t[n-4] == 0
end

function cond_b(t, n)
   return t[n] == 1 and t[n-1] == 1 and t[n-2] == 0
end

function extract_fractal_and_print(t)
   local counter, cnt_t = (level == 0 and 1 or 0), {}
   for i = 1, #t do
      if i < 9 then print(df[i]) end
      if i > 3 then
         counter = counter + 1
         if cond_a(df, i) and counter == 5 then
            cnt_t[#cnt_t+1] = 1
            counter = 0
         elseif cond_b(df, i) and counter == 3 then
            cnt_t[#cnt_t+1] = 0
            counter = 0
         elseif counter > 5 then
            print("XXXX")
            cnt_t[#cnt_t+1] = "XXXX"
         end
      end
   end
   return cnt_t
end

level = 0
repeat
   print("Level: " .. level)
   df = extract_fractal_and_print(df)
   level = level + 1
until #df < 15
print("End:")
print(table.concat(df, "\n"))