window 1, @"Feignenbaum Constant", ( 0, 0, 200, 300 )

_maxIt  = 13
_maxItJ = 10

void local fn Feignenbaum
  NSUInteger i, j, k
  double     a1 = 1.0, a2 = 0.0, d1 = 3.2

  print "Feignenbaum Constant"
  print " i       d"

  for i = 2 to _maxIt
    double a = a1 + ( a1 - a2 ) / d1
    for j = 1 to _maxItJ
      double x = 0, y = 0
      for k = 1 to fn pow( 2, i )
        y = 1 - 2 * y * x
        x = a - x * x
      next
      a = a - x / y
    next
    double d = ( a1 - a2 ) / ( a - a1 )
    printf @"%2d.   %.8f", i, d
    d1 = d
    a2 = a1
    a1 = a
  next
end fn

fn Feignenbaum

HandleEvents