Find Local Extrema

Find local maxima and minima in the Live Editor

Description

The Find Local Extrema task lets you interactively find local maxima and local minima in data. The task automatically generates MATLAB^® code for your live script.

Using this task, you can:

• Find local maxima, minima, or both in data from a workspace variable.

• Adjust parameters to locate fewer or more extrema.

• Automatically visualize the detected extrema.

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Open the Task

To add the Find Local Extrema task to a live script in the MATLAB Editor:

• On the Live Editor tab, select Task > Find Local Extrema.

• In a code block in the script, type a relevant keyword, such as extrema or find. Select Find Local Extrema from the suggested command completions.

Examples

Related Examples

• Add Interactive Tasks to a Live Script
• Clean Messy Data and Locate Extrema Using Live Editor Tasks

Parameters

Input data — Valid input data from workspace

vector | table | timetable | ...

This task operates on data of type single, double, or logical, or signed or unsigned integer types such as int64. The data can be contained in a vector or table variables. When providing a table or timetable for the input data, specify All supported variables to operate on all variables with a supported type. Choose All numeric variables to operate on all variables of type single or double, or signed or unsigned integer types. To choose specific supported variables to operate on, select Specified variables and then select the variables individually.

Flat selection — Flat region indicator

Center (default) | First | Last | All

Specify a flat region indicator when you have local consecutive extrema values.

Method	Description
Center	Indicates only the center element of a flat region as the local extrema.
First	Indicates only the first element of a flat region as the local extrema.
Last	Indicates only the last element of a flat region as the local extrema.
All	Indicates all the elements of a flat region as the local extrema.

Min. prominence — Minimum prominence of extrema

0 (default) | positive scalar | ...

Specify a minimum prominence to return only local extrema whose prominence is at least that value. Higher prominence values return fewer detected extrema.

The prominence of a local maximum (or peak) is a measure of how the peak stands out with respect to its height and location relative to other peaks. The prominence of a local minimum (or valley) is a measure of how the valley stands out with respect to its depth and location relative to other valleys.

Prominence window — Window for computing prominence

Centered (default) | Asymmetric

Specify a prominence window type and size to define a window of neighboring points for which to compute the prominence for each local extrema.

Window	Description
Centered	Specified window length centered about the current point.
Asymmetric	Specified window containing the number of elements before the current point and the number of elements after the current point.

Window sizes are relative to the X-axis variable units.