In SciPy >= 0.11
import numpy as np
from scipy.signal import argrelextrema
x = np.random.random(12)
# for local maxima
argrelextrema(x, np.greater)
# for local minima
argrelextrema(x, np.less)
Produces
>>> x
array([ 0.56660112, 0.76309473, 0.69597908, 0.38260156, 0.24346445,
0.56021785, 0.24109326, 0.41884061, 0.35461957, 0.54398472,
0.59572658, 0.92377974])
>>> argrelextrema(x, np.greater)
(array([1, 5, 7]),)
>>> argrelextrema(x, np.less)
(array([4, 6, 8]),)
Note, these are the indices of x that are local max/min. To get the values, try:
>>> x[argrelextrema(x, np.greater)[0]]
scipy.signal
also provides argrelmax
and argrelmin
for finding maxima and minima respectively.