# getDelayInfo

Get input/output delay information for `idnlarx`

model
structure

## Syntax

`DELAYS = getDelayInfo(MODEL)`

DELAYS = getDelayInfo(MODEL,TYPE)

## Description

`DELAYS = getDelayInfo(MODEL)`

obtains the maximum delay in each
input and output variable of an `idnlarx`

model.

`DELAYS = getDelayInfo(MODEL,TYPE)`

lets you choose between
obtaining maximum delays across all input and output variables or maximum delays for
each output variable individually. When delays are obtained for each output variable
individually a matrix is returned, where each row is a vector containing
*n _{y}*+

*n*maximum delays for each output variable, and:

_{u}*n*is the number of outputs of_{y}`MODEL`

.*n*is the number of inputs of_{u}`MODEL`

.

Delay information is useful for determining the number of states in the model. For
nonlinear ARX models, the states are related to the set of delayed input and output
variables that define the model structure (regressors). For example, if an input or
output variable *p* has a maximum delay of *D*
samples, then it contributes *D* elements to the state vector:

*p*(*t*-1),
*p*(*t*-2),
...*p*(*t*-*D*)

The number of states of a nonlinear ARX model equals the sum of the maximum delays of
each input and output variable. For more information about the definition of states for
`idnlarx`

models, see Definition of idnlarx States

## Input Arguments

`getDelayInfo`

accepts the following arguments:

`MODEL`

:`idnlarx`

model.`TYPE`

: (Optional) Specifies whether to obtain channel delays`'channelwise'`

or`'all'`

as follows:`'all'`

: Default value.`DELAYS`

contains the maximum delays across each output (vector of*n*+_{y}*n*entries, where_{u}`[ny, nu] = size(MODEL)`

).`'channelwise'`

:`DELAYS`

contains delay values separated for each output (*n*-by-(_{y}*n*+_{y}*n*) matrix)._{u}

## Output Arguments

`DELAYS`

: Contains delay information in a vector of length*n*+_{y}*n*arranged with output channels preceding the input channels, i.e.,_{u}`[y1, y2,.., u1, u2,..]`

.

## Examples

## Version History

**Introduced in R2008b**

## See Also

`data2state`

| `getreg`

| `idnlarx`