/*

  Test of Collatz (Hailstone) function

  n n/2 (n is even)
  n 3n + 1 (n is odd)

  This is hard.

  * point seq
  
    Gen 6131
    [program = if_then_else(A mod 2,1 + A * 3,A div 2),res = 34,count = 1]

  * make_seq n=2

    gen = 220
    [program = 1 div if_then_else(1,B,1) * (0 != A) + (A - 0) + (A + B) div B,res = 34,count = 1]

    gen 2528
    [program = (B div B - (0 - A)) * (B + 1) div B,res = 34,count = 1]

    gen = 234
    [program = ((A != 1 * (A mod A)) + A) div B + ((1 != 0 div (0 - B)) + A),res = 34,count = 1]


    gen = 1056
    [program = 1 + A + (A + (A - 3 == (0 == 0))) div B,res = 34,count = 1]


*/
data(collatz,Data,Vars,Unknown,Ops,Constants,MaxSize,Params) :-
  Seq = [collatz(I) : I in 1..10],
  println(seq=Seq),
  (
    % make_point_seq(Seq,Data,Unknown,Vars)
    % ; 
    member(N,2..2),
    % println(n=N),
    make_seq(Seq,N,Data,Unknown,Vars)
  ),
  Ops = [+,*,-,div,mod,if_then_else,==,!=],
  Constants = 0..3,%  ++ [random(-10,10) : _ in 1..10],          
  MaxSize = 11,
  Params = new_map([init_size=500]).


collatz(N) = N//2, N mod 2 == 0 => true.
collatz(N) = 3*N+1 => true.