Module « matplotlib.pyplot »

Fonction xcorr - module matplotlib.pyplot

Signature de la fonction xcorr

def xcorr(x, y, normed=True, detrend=<function detrend_none at 0x7f5050c634c0>, usevlines=True, maxlags=10, *, data=None, **kwargs) 

Description

xcorr.__doc__

Plot the cross correlation between *x* and *y*.

The correlation with lag k is defined as
:math:`\sum_n x[n+k] \cdot y^*[n]`, where :math:`y^*` is the complex
conjugate of :math:`y`.

Parameters
----------
x, y : array-like of length n

detrend : callable, default: `.mlab.detrend_none` (no detrending)
    A detrending function applied to *x* and *y*.  It must have the
    signature ::

        detrend(x: np.ndarray) -> np.ndarray

normed : bool, default: True
    If ``True``, input vectors are normalised to unit length.

usevlines : bool, default: True
    Determines the plot style.

    If ``True``, vertical lines are plotted from 0 to the xcorr value
    using `.Axes.vlines`. Additionally, a horizontal line is plotted
    at y=0 using `.Axes.axhline`.

    If ``False``, markers are plotted at the xcorr values using
    `.Axes.plot`.

maxlags : int, default: 10
    Number of lags to show. If None, will return all ``2 * len(x) - 1``
    lags.

Returns
-------
lags : array (length ``2*maxlags+1``)
    The lag vector.
c : array  (length ``2*maxlags+1``)
    The auto correlation vector.
line : `.LineCollection` or `.Line2D`
    `.Artist` added to the Axes of the correlation:

    - `.LineCollection` if *usevlines* is True.
    - `.Line2D` if *usevlines* is False.
b : `.Line2D` or None
    Horizontal line at 0 if *usevlines* is True
    None *usevlines* is False.

Other Parameters
----------------
linestyle : `.Line2D` property, optional
    The linestyle for plotting the data points.
    Only used if *usevlines* is ``False``.

marker : str, default: 'o'
    The marker for plotting the data points.
    Only used if *usevlines* is ``False``.

**kwargs
    Additional parameters are passed to `.Axes.vlines` and
    `.Axes.axhline` if *usevlines* is ``True``; otherwise they are
    passed to `.Axes.plot`.

Notes
-----
The cross correlation is performed with `numpy.correlate` with
``mode = "full"``.

.. note::
    In addition to the above described arguments, this function can take
    a *data* keyword argument. If such a *data* argument is given,
    the following arguments can also be string ``s``, which is
    interpreted as ``data[s]`` (unless this raises an exception):
    *x*, *y*.

    Objects passed as **data** must support item access (``data[s]``) and
    membership test (``s in data``).