scientimate.findextremum

xmin, ymin, xmax, ymax = scientimate.findextremum(x, y, winlen=3, dispout='no')

Description

Find local extremum (minimum and maximum) in data

Inputs

x

x data

y

y data

winlen=3

Window length, defines a number of points in sliding window used for defining maximum and minimum

Example: winlen=5 means two points on each side of each data point is used in calculation

Using a larger value for winlen makes it less sensitive

winlen should be an odd number equal or larger than 3

dispout=’no’

Define to display outputs or not (‘yes’: display, ‘no’: not display)

Outputs

xmin

x of minmum points

ymin

y of minmum points

xmax

x of maximum points

ymax

y of maximum points

Examples

import scientimate as sm
import numpy as np

x=np.linspace(0,30,1000)
y=2*np.exp(-0.1*2*np.pi/5*x)*np.sin(np.sqrt(1-0.1**2)*2*np.pi/5*x)
xmin,ymin,xmax,ymax=sm.findextremum(x,y,3,'yes')

x=np.linspace(0,50,1000)
y=np.sin(x)+0.1*np.random.rand(1000)
xmin,ymin,xmax,ymax=sm.findextremum(x,y,15,'yes')

References