def buttap(N):
 if (abs(int(N)) != N):
  raise ValueError('Filter order must be a nonnegative integer')
 z = numpy.array([])
 m = numpy.arange(((- N) + 1), N, 2)
 p = (- numpy.exp((((1j * pi) * m) / (2 * N))))
 k = 1
 return (z, p, k)

def buttap ( N ) : if ( abs ( int ( N ) ) != N ) : raise ValueError ( 'Filter order must be a nonnegative integer' ) z = numpy . array ( [ ] ) m = numpy . arange ( ( ( - N ) + 1 ) , N , 2 ) p = ( - numpy . exp ( ( ( ( 1j * pi ) * m ) / ( 2 * N ) ) ) ) k = 1 return ( z , p , k )
return for analog prototype of nth-order butterworth filter .