SciPy

scipy.signal.argrelextrema

scipy.signal.argrelextrema(data, comparator, axis=0, order=1, mode='clip')[source]

Calculate the relative extrema of data.

New in version 0.11.0.

Parameters :

data : ndarray

Array in which to find the relative extrema.

comparator : callable

Function to use to compare two data points. Should take 2 numbers as arguments.

axis : int, optional

Axis over which to select from data. Default is 0.

order : int, optional

How many points on each side to use for the comparison to consider comparator(n, n+x) to be True.

mode : str, optional

How the edges of the vector are treated. ‘wrap’ (wrap around) or ‘clip’ (treat overflow as the same as the last (or first) element). Default is ‘clip’. See numpy.take.

Returns :

extrema : tuple of ndarrays

Indices of the maxima in arrays of integers. extrema[k] is the array of indices of axis k of data. Note that the return value is a tuple even when data is one-dimensional.

See also

argrelmin, argrelmax

Examples

>>> x = np.array([2, 1, 2, 3, 2, 0, 1, 0])
>>> argrelextrema(x, np.greater)
(array([3, 6]),)
>>> y = np.array([[1, 2, 1, 2],
...               [2, 2, 0, 0],
...               [5, 3, 4, 4]])
...
>>> argrelextrema(y, np.less, axis=1)
(array([0, 2]), array([2, 1]))