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Python Result.expect[e_idx][t_idx]方法代碼示例

本文整理匯總了Python中qutip.solver.Result.expect[e_idx][t_idx]方法的典型用法代碼示例。如果您正苦於以下問題:Python Result.expect[e_idx][t_idx]方法的具體用法?Python Result.expect[e_idx][t_idx]怎麽用?Python Result.expect[e_idx][t_idx]使用的例子?那麽, 這裏精選的方法代碼示例或許可以為您提供幫助。您也可以進一步了解該方法所在qutip.solver.Result的用法示例。


在下文中一共展示了Result.expect[e_idx][t_idx]方法的1個代碼示例,這些例子默認根據受歡迎程度排序。您可以為喜歡或者感覺有用的代碼點讚,您的評價將有助於係統推薦出更棒的Python代碼示例。

示例1: fsesolve

# 需要導入模塊: from qutip.solver import Result [as 別名]
# 或者: from qutip.solver.Result import expect[e_idx][t_idx] [as 別名]
def fsesolve(H, psi0, tlist, e_ops=[], T=None, args={}, Tsteps=100):
    """
    Solve the Schrodinger equation using the Floquet formalism.

    Parameters
    ----------

    H : :class:`qutip.qobj.Qobj`
        System Hamiltonian, time-dependent with period `T`.

    psi0 : :class:`qutip.qobj`
        Initial state vector (ket).

    tlist : *list* / *array*
        list of times for :math:`t`.

    e_ops : list of :class:`qutip.qobj` / callback function
        list of operators for which to evaluate expectation values. If this
        list is empty, the state vectors for each time in `tlist` will be
        returned instead of expectation values.

    T : float
        The period of the time-dependence of the hamiltonian.

    args : dictionary
        Dictionary with variables required to evaluate H.

    Tsteps : integer
        The number of time steps in one driving period for which to
        precalculate the Floquet modes. `Tsteps` should be an even number.

    Returns
    -------

    output : :class:`qutip.solver.Result`

        An instance of the class :class:`qutip.solver.Result`, which
        contains either an *array* of expectation values or an array of
        state vectors, for the times specified by `tlist`.
    """

    if not T:
        # assume that tlist span exactly one period of the driving
        T = tlist[-1]

    # find the floquet modes for the time-dependent hamiltonian
    f_modes_0, f_energies = floquet_modes(H, T, args)

    # calculate the wavefunctions using the from the floquet modes
    f_modes_table_t = floquet_modes_table(f_modes_0, f_energies,
                                          np.linspace(0, T, Tsteps + 1),
                                          H, T, args)

    # setup Result for storing the results
    output = Result()
    output.times = tlist
    output.solver = "fsesolve"

    if isinstance(e_ops, FunctionType):
        output.num_expect = 0
        expt_callback = True

    elif isinstance(e_ops, list):

        output.num_expect = len(e_ops)
        expt_callback = False

        if output.num_expect == 0:
            output.states = []
        else:
            output.expect = []
            for op in e_ops:
                if op.isherm:
                    output.expect.append(np.zeros(len(tlist)))
                else:
                    output.expect.append(np.zeros(len(tlist), dtype=complex))

    else:
        raise TypeError("e_ops must be a list Qobj or a callback function")

    psi0_fb = psi0.transform(f_modes_0)
    for t_idx, t in enumerate(tlist):
        f_modes_t = floquet_modes_t_lookup(f_modes_table_t, t, T)
        f_states_t = floquet_states(f_modes_t, f_energies, t)
        psi_t = psi0_fb.transform(f_states_t, True)

        if expt_callback:
            # use callback method
            e_ops(t, psi_t)
        else:
            # calculate all the expectation values, or output psi if
            # no expectation value operators where defined
            if output.num_expect == 0:
                output.states.append(Qobj(psi_t))
            else:
                for e_idx, e in enumerate(e_ops):
                    output.expect[e_idx][t_idx] = expect(e, psi_t)

    return output
開發者ID:Marata459,項目名稱:qutip,代碼行數:101,代碼來源:floquet.py


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