#import std
#import nat

iterative_fib = ~&/(0,1); ~&r->ll ^|\predecessor ^/~&r sum

recursive_fib = {0,1}^?<a/~&a sum^|W/~& predecessor^~/~& predecessor

analytical_fib =

%np+ -+
   mp..round; ..mp2str; sep`+; ^CNC/~&hh take^\~&htt %np@t,
   (mp..div^|\~& mp..sub+ ~~ @rlX mp..pow_ui)^lrlPGrrPX/~& -+
      ^\~& ^(~&,mp..sub/1.E0)+ mp..div\2.E0+ mp..add/1.E0,
      mp..sqrt+ ..grow/5.E0+-+-