Identity Matrix

R2026b

Generate matrix with ones on main diagonal and ground values elsewhere

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  • Identity Matrix block

Libraries:
Simulink / Matrix Operations

Description

The Identity Matrix block outputs an identity matrix, similar to the MATLAB® eye function. The block generates a square or rectangular matrix with ones on the main diagonal and zeros elsewhere.

Examples

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Open Model

This example shows how to generate a 3-by-6 unit-diagonal matrix and a 5-by-5 identity matrix using the Identity Matrix block.

Ports

Input

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Input signal used to determine dimensions of the output matrix, specified as a scalar, vector, or matrix. When the input signal is an M-by-N matrix, the block generates an M-by-N matrix output with the same sample period as the input. The values in the input matrix are ignored.

Dependencies

To enable this port, select the Inherit output port attributes from input port check box.

Data Types: single | double | half | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point

Output

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Identity matrix, specified as a scalar, vector, or matrix.

Data Types: single | double | half | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point

Parameters

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Select this check box for the output port to inherit its dimensions, sample period, and data type from the input port. Otherwise, clear this check box.

Programmatic Use

Block Parameter: InheritOutputPortAttributes
Type: character vector
Values: 'on' | 'off'
Default: 'off'

The number of rows and columns in the output matrix. You can specify:

  • A positive integer scalar M to create a square M-by-M output.

  • A vector of positive integers, [M N], to create an M-by-N output.

Dependencies

To enable this parameter, clear the Inherit output port attributes from input port check box.

Programmatic Use

Block Parameter: OutputDimensions
Type: character vector
Values: scalar | two-element vector
Default: '5'

Specify the output data type for this block. You can select one of these options:

  • A rule that inherits a data type, for example, Inherit: Inherit via back propagation. When you select this option, the output data type and scaling matches that of the next downstream block.

  • A built-in data type, such as double.

  • An expression that evaluates to a valid data type, for example, fixdt(1,16).

For help setting data type parameters, display the Data Type Assistant by clicking the Show data type assistant button .

See Control Data Types of Signals for more information.

Programmatic Use

Block Parameter: OutDataTypeStr
Type: character vector
Values: 'Inherit: Inherit via back propagation' | 'double' | 'single' | 'half' | 'int8' | 'uint8' | 'int16' | 'uint16' | 'int32' | 'uint32' | 'int64' | 'uint64' | | 'fixdt(1,16,0)' | '<data type expression>'
Default: 'double'

Select how you would like to specify the data type properties of the Output data type. You can choose:

  • Inherit — Specify a rule for inheriting a data type, for example, Inherit: Same as input.

  • Built in— Specify a built-in data type, for example, double.

  • Fixed point — Specify the fixed-point attributes of the data type.

  • Expression — Specify an expression that evaluates to a valid data type, for example, fixdt(1,16).

For more information, see Specify Data Types Using Data Type Assistant.

Specify whether the fixed-point data is signed or unsigned. Signed data can represent positive and negative values, but Unsigned data represents positive values only. For more information, see Specify Data Types Using Data Type Assistant.

Specify the method for scaling your fixed-point data to avoid overflow conditions and minimize quantization errors. For more information, see Specify Data Types Using Data Type Assistant.

Dependencies

To enable this parameter, set Mode to Fixed point

Specify the bit size of the word that holds the quantized integer as a positive integer from 2 to 65,535. For more information, see Specify Data Types Using Data Type Assistant.

Dependencies

To enable this parameter, set Mode to Fixed point.

Specify the fraction length of the fixed-point data type as a positive or negative integer scalar.

Dependencies

To enable this parameter, set Mode to Fixed point and Scaling to Binary point.

Select the data type override mode for this signal. You can select:

  • Inherit — Inherits the data type override setting specified for the model.

  • Off — Ignores the data type override setting specified for the model and uses the fixed-point data type you specify.

Dependencies

To enable this parameter, set Mode to Built in or Fixed point. For more information, see Specify Data Types Using Data Type Assistant.

The discrete sample period of the output, specified as a real-valued scalar.

Dependencies

To enable this parameter, clear the Inherit output port attributes from input port check box.

Programmatic Use

Block Parameter: SampleTime
Type: character vector
Values: scalar or vector
Default: '1'

Block Characteristics

Data Types

Boolean | double | fixed point | half | 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/IdentityMatrix"

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

Extended Capabilities

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C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2021b

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See Also

Functions

Blocks

Topics