qiskit/tools/qi/qi.py
def entanglement_of_formation(state, d0, d1=None):
    """
    Compute the entanglement of formation of quantum state.

    The input quantum state must be either a bipartite state vector, or a
    2-qubit density matrix.

    Args:
        state (array_like): (N) array_like or (4,4) array_like, a
            bipartite quantum state.
        d0 (int): the dimension of the first subsystem.
        d1 (int or None): the dimension of the second subsystem.

    Returns:
        float: The entanglement of formation.
    """
    state = np.array(state)

    if d1 is None:
        d1 = int(len(state) / d0)

    if state.ndim == 2 and len(state) == 4 and d0 == 2 and d1 == 2:
        return __eof_qubit(state)
    elif state.ndim == 1:
        # trace out largest dimension
        if d0 < d1:
            tr = [1]
        else:
            tr = [0]
        state = partial_trace(state, tr, dimensions=[d0, d1])
        return entropy(state)
    else:
        print('Input must be a state-vector or 2-qubit density matrix.')
    return None
def entanglement_of_formation(state, d0, d1=None):
    state = np.array(state)

    if d1 is None:
        d1 = int(len(state) / d0)

    if state.ndim == 2 and len(state) == 4 and d0 == 2 and d1 == 2:
        return __eof_qubit(state)
    elif state.ndim == 1:
        # trace out largest dimension
        if d0 < d1:
            tr = [1]
        else:
            tr = [0]
        state = partial_trace(state, tr, dimensions=[d0, d1])
        return entropy(state)
    else:
        print('Input must be a state-vector or 2-qubit density matrix.')
    return None
def entanglement_of_formation ( state , d0 , d1 = None ) : state = np . array ( state ) if d1 is None : d1 = int ( len ( state ) / d0 ) if state . ndim == 2 and len ( state ) == 4 and d0 == 2 and d1 == 2 : return __eof_qubit ( state ) elif state . ndim == 1 : # trace out largest dimension if d0 < d1 : tr = [ 1 ] else : tr = [ 0 ] state = partial_trace ( state , tr , dimensions = [ d0 , d1 ] ) return entropy ( state ) else : print ( 'Input must be a state-vector or 2-qubit density matrix.' ) return None
Compute the entanglement of formation of quantum state.

    The input quantum state must be either a bipartite state vector, or a
    2-qubit density matrix.

    Args:
        state (array_like): (N) array_like or (4,4) array_like, a
            bipartite quantum state.
        d0 (int): the dimension of the first subsystem.
        d1 (int or None): the dimension of the second subsystem.

    Returns:
        float: The entanglement of formation.
Compute the entanglement of formation of quantum state .