def __eof_qubit(rho):
c = concurrence(rho)<EOL>c = <NUM_LIT:0.5> + <NUM_LIT:0.5> * np.sqrt(<NUM_LIT:1> - c * c)<EOL>return shannon_entropy([c, <NUM_LIT:1> - c])<EOL>
Compute the Entanglement of Formation of a 2-qubit density matrix.

Args:
    rho ((array_like): (4,4) array_like, input density matrix.

Returns:
    float: The entanglement of formation.