# exp( - j 2 pi k / N ) = W^k_N

from math import exp, cos, sin, pi

class TwiddleFactors(object):
	"""docstring for TwiddleFactors"""
	def __init__(self, N):
		super (TwiddleFactors, self).__init__()
		self.N = N
		self.w = []
		self.w_int = []

	def build_twiddle_factors(self):
		w = []
		for k in range( self.N / 2 ):
			teta = - 2 * pi * k / self.N
			w.append(  cos ( teta ) + 1j * sin( teta ) )
		self.w = w[:]
		return w

	def twiddle_factors_dot_vhd_generation(self):
		print 'size of w = ', len(self.w)
		nb_bits = 16
		print self.w
		for k in range( self.N / 2 ):
			w_int_re = int(self.w[k].real * 2**(nb_bits-1))
			w_int_im = int(self.w[k].imag * 2**(nb_bits-1))
			self.w_int.append(  w_int_re + 1j * w_int_im )
		print self.w_int
		pass