galois.FLFSR.Taps

classmethod galois.FLFSR.Taps(taps: FieldArray, state: ArrayLike | None = None) → Self

Constructs a Fibonacci LFSR from its taps $T = [c_{n - 1}, c_{n - 2}, \dots, c_{1}, c_{0}]$ .

Parameters:¶

taps: FieldArray¶: The shift register taps $T = [c_{n - 1}, c_{n - 2}, \dots, c_{1}, c_{0}]$ .
state: ArrayLike | None = None¶: The initial state vector $S = [S_{0}, S_{1}, \dots, S_{n - 2}, S_{n - 1}]$ . The default is None which corresponds to all ones.

Returns:¶

A Fibonacci LFSR with taps $T = [c_{n - 1}, c_{n - 2}, \dots, c_{1}, c_{0}]$ .

Examples¶

In [1]: c = galois.primitive_poly(7, 4); c
Out[1]: Poly(x^4 + x^2 + 3x + 5, GF(7))

In [2]: taps = -c.coeffs[1:]; taps
Out[2]: GF([0, 6, 4, 2], order=7)

In [3]: lfsr = galois.FLFSR.Taps(taps)

In [4]: print(lfsr)
Fibonacci LFSR:
  field: GF(7)
  feedback_poly: 5x^4 + 3x^3 + x^2 + 1
  characteristic_poly: x^4 + x^2 + 3x + 5
  taps: [0 6 4 2]
  order: 4
  state: [1 1 1 1]
  initial_state: [1 1 1 1]