Extract Diagonal

R2026b

Extract main diagonal of input matrix

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Extract Diagonal block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
Simulink / Matrix Operations

Description

The Extract Diagonal block populates the unoriented output vector with the elements on the main diagonal of the M-by-N input matrix A.

Equivalent MATLAB^® code is given by:

D = diag(A)

Examples

Extract Diagonal of Matrix

This example shows how to use the Extract Diagonal block.

Open the Simulink model.

The Extract Diagonal block returns the main diagonal of the input matrix. The main diagonal of the input matrix is [1,5,9].

Run the model to verify.

Ports

Input

Port_1 — Input signal

scalar | vector | matrix

Input matrix to extract the diagonal from, specified as a scalar, vector, or matrix.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32 | Boolean | fixed point
Complex Number Support: Yes

Output

Port_1 — Output signal

vector

Output vector of each diagonal element.

The output is the same data type and complexity as the input. The output vector has length min(M,N).

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32 | Boolean | fixed point
Complex Number Support: Yes

Block Characteristics

Data Types	Boolean | double | fixed point | integer | single
Direct Feedthrough	no
Multidimensional Signals	no
Variable-Size Signals	no
Zero-Crossing Detection	no

Programmatic Use: Add Block

To add the block programmatically, use the add_block function with one of these library block paths as the source.

"simulink/Matrix Operations/Extract Diagonal"

Example: add_block("simulink/Matrix Operations/Extract Diagonal","myModel/myBlock",MakeNameUnique="on")

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using Simulink® Coder™.

Generated code relies on the memcpy or memset function (string.h) under certain conditions.

Fixed-Point Conversion
Design and simulate fixed-point systems using Fixed-Point Designer™.

Version History

Introduced before R2006a

R2021b: Extract Diagonal Block Moved to Simulink Matrix Operations Library

The Extract Diagonal block has been moved from the DSP System Toolbox > Math Functions > Matrices and Linear Algebra > Matrix Operations library to the Simulink > Matrix Operationslibrary. All existing models continue to work.