cupyx.scipy.signal.argrelmax#

cupyx.scipy.signal.argrelmax(data, axis=0, order=1, mode='clip')[source]#

Calculate the relative maxima of data.

Parameters:

  • data (ndarray) – Array in which to find the relative maxima.

  • 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. Available options are ‘wrap’ (wrap around) or ‘clip’ (treat overflow as the same as the last (or first) element). Default ‘clip’. See cupy.take.

Returns:

extrema – 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.

Return type:

tuple of ndarrays

See also

argrelextrema, argrelmin, find_peaks

Notes

This function uses argrelextrema with cupy.greater as comparator. Therefore it requires a strict inequality on both sides of a value to consider it a maximum. This means flat maxima (more than one sample wide) are not detected. In case of one-dimensional data find_peaks can be used to detect all local maxima, including flat ones.

Examples

>>> from cupyx.scipy.signal import argrelmax
>>> import cupy
>>> x = cupy.array([2, 1, 2, 3, 2, 0, 1, 0])
>>> argrelmax(x)
(array([3, 6]),)
>>> y = cupy.array([[1, 2, 1, 2],
...               [2, 2, 0, 0],
...               [5, 3, 4, 4]])
...
>>> argrelmax(y, axis=1)
(array([0]), array([1]))