Find Local Extrema
Find local maxima and minima in the Live Editor
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.
Visualize the detected extrema.
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
find. Select Find Local Extrema from the suggested command completions.
Input data — Valid input data from workspace
vector | table | timetable
This task operates on input data contained in a vector, table, or timetable. The
data can be of type
logical, or signed or unsigned integer types such as
When providing a table or timetable for the input data, select
supported variables to operate on all variables with a supported type.
All numeric variables to operate on all variables of
double, or signed or unsigned
integer types. To choose specific supported variables to operate on, select
Specified variables and then select the variables
Flat selection — Flat region indicator
Center (default) |
Specify a flat region indicator when you have local consecutive extrema values.
|Indicates only the center element of a flat region as the local extrema|
|Indicates only the first element of a flat region as the local extrema|
|Indicates only the last element of a flat region as the local extrema|
|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) |
Specify a prominence window type and size to define a window of neighboring points for which to compute the prominence for each local extrema.
|Specified window length centered about the current point|
|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.
Version HistoryIntroduced in R2019b
R2022b: Plot multiple table variables
Simultaneously plot multiple table variables in the display of this Live Editor task. For table or timetable data, to visualize all selected table variables at once in a tiled chart layout, set the Variable to display field.
R2022b: Specify tabular output
Output a table or timetable with logical variables corresponding to the table variables checked for local extrema, or append the logical variables to the input table. For table or timetable input data, to specify the tabular format, set the Output format field.
R2022a: Live Editor task does not run automatically if inputs have more than 1 million elements
This Live Editor task does not run automatically if the inputs have more than 1 million elements. In previous releases, the task always ran automatically for inputs of any size. If the inputs have a large number of elements, then the code generated by this task can take a noticeable amount of time to run (more than a few seconds).
When a task does not run automatically, the Autorun icon is disabled.
To run a task manually, on the Live Editor tab, click the Run Section button.
To enable running the section automatically, click the Autorun icon. The icon updates to display the enabled state.
R2021a: Operate on multiple table variables
This Live Editor task can operate on multiple table variables at the same time. For table
or timetable input data, to operate on multiple variables, select
Specified variables. Return all of
the variables or only the modified variables, and specify which variable to