Interactively estimate the approximate entropy of a uniformly sampled signal in the Live Editor

The **Estimate Approximate Entropy** task lets you
interactively estimate the approximate entropy of a uniformly sampled signal. The task
automatically generates MATLAB^{®} code for your live script. For more information about Live Editor tasks
generally, see Add Interactive Tasks to a Live Script (MATLAB).

Approximate entropy is a regularity statistic that quantifies the unpredictability of fluctuations in a time series. A relatively higher value of approximate entropy reflects the likelihood that similar patterns of observations are not followed by additional similar observations.

To add the **Estimate Approximate Entropy** task to a live
script in the MATLAB Editor:

On the

**Live Editor**tab, select**Task**>**Estimate Approximate Entropy**.In a code block in your script, type a relevant keyword, such as

`approximate`

or`approximate entropy`

. Select`Estimate Approximate Entropy`

from the suggested command completions.

`Signal`

— Uniformly sampled time-domain signalarray | timetable

Select a uniformly sampled time-domain signal in array or timetable format. If the
signal has multiple columns, the **Estimate Approximate
Entropy** task computes the approximate entropy by treating it as a
multivariate signal. If the signal is a row vector, then the **Estimate
Approximate Entropy** task treats it as a univariate signal.

`Embedding Dimension`

— Number of dimensions of phase space vectorsscalar | vector

Specify the number of dimensions of phase space vectors as a scalar or vector from the MATLAB workspace. When you specify the embedding dimension as a scalar, then every column of the uniformly sampled signal is computed using the same embedding dimension value.

If you do not know the value of embedding dimension for your signal, then you can
compute it using the **Reconstruct Phase
Space** task.

`Time Lag`

— Time lag between successive phase vectorsscalar | vector

Specify time lag between successive phase vectors as a scalar or vector from the
MATLAB workspace. When you specify the time lag as a scalar, then the
**Estimate Approximate Entropy** task uses the same time
delay value to estimate the value of approximate entropy for all the columns of the
uniformly sampled signal. If you specify the embedding dimension as a vector, then
specify the time lag also as a vector of the same length.

If you do not know the value of time lag for your signal, then you can compute it
using the **Reconstruct Phase
Space** task.

`Radius`

— Similarity criterion`'Auto'`

(default) | scalarSpecify similarity criterion as a scalar. The similarity criterion, also called radius of similarity, is a tuning parameter that is used to identify a meaningful range in which fluctuations in data are to be considered similar.

`Output Display`

— Toggle result display in the Live Editor outputon (default) | off

Toggle to display the value of approximate entropy in the Live Editor output.

Reconstruct Phase
Space | `approximateEntropy`

| `correlationDimension`

| `lyapunovExponent`

| `phaseSpaceReconstruction`