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Iterator Subsystems

Configure subsystems for repeated execution

An iterator subsystem runs one or more times at the current time step when enabled by a control block. A control block implements control logic similar to that expressed by programming language loop constructs such as while or for.

These iterator subsystems apply to general use cases:

  • While Iterator Subsystem block — Repeat execution of an algorithm as long as a logical condition is true.

  • For Iterator Subsystem block — Repeat execution of an algorithm until an iteration variable exceeds a specified iteration limit.

  • For Each Subsystem block — Apply an algorithm to individual elements or subarrays of input signals or mask parameters.

These iterator subsystems implement the neighborhood pattern and are optimized for large input data such as images and video:

  • Neighborhood Processing Subsystem block — Apply an algorithm that follows the neighborhood pattern.

  • Pixel Processing Subsystem block — Apply an algorithm to multichannel data such as pixels in image data.

  • Array Processing Subsystem block — Apply an algorithm to each element of a large array.

Each block inside a For Each subsystem that has states maintains a separate set of states for each element or subarray processed by the subsystem. By contrast, blocks inside While Iterator and For Iterator subsystems use the same states throughout successive iterations of the subsystem. The neighborhood processing iterator subsystems do not have states.

Blocks

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While Iterator Subsystem Repeat subsystem execution during simulation time step while logical expression is true
For Iterator Subsystem Repeat subsystem execution during simulation time step for specified number of iterations
For Each SubsystemApply algorithm to individual elements or subarrays of input signals or mask parameters
Neighborhood Processing SubsystemCreate algorithm that follows the neighborhood pattern (Since R2022b)
Pixel Processing SubsystemCreate algorithm that converts multichannel image data to single-channel (Since R2024a)
Array Processing SubsystemApply algorithm to each element of a matrix (Since R2024a)

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