Identity Matrix - Generate matrix with ones on main diagonal and zeros elsewhere

Library

Description

The Identity Matrix block generates a rectangular matrix with ones on the main diagonal and zeros elsewhere.

When you select the Inherit output port attributes from input port check box, the input port is enabled, and an M-by-N matrix input generates a sample-based M-by-N matrix output with the same sample period. The values in the input matrix are ignored.

y = eye([M N])						% Equivalent MATLAB code 

When you do not select the Inherit output port attributes from input port check box, the input port is disabled, and the dimensions of the output matrix are determined by the Matrix size parameter. A scalar value, M, specifies an M-by-M identity matrix, while a two-element vector, [M N], specifies an M-by-N unit-diagonal matrix. The output is sample based, and has the sample period specified by the Sample time parameter.

Examples

Set Matrix size to [3 6] to generate the 3-by-6 unit-diagonal matrix below.

Dialog Box

The Main pane of the Identity Matrix block dialog appears as follows.

Inherit output port attributes from input port

Enables the input port when selected. In this mode, the output inherits its dimensions, sample period, and data type from the input. The output is always real.

Matrix size

The number of rows and columns in the output matrix: a scalar M for a square M-by-M output, or a vector [M N] for an M-by-N output. This parameter is disabled when you select Inherit input port attributes from input port.

Sample time

The discrete sample period of the output. This parameter is disabled when you select Inherit input port attributes from input port.

The Data Types pane of the Identity Matrix block dialog appears as follows.

Output data type

Specify the output data type in one of the following ways:

Signed

Select to output a signed fixed-point signal. Otherwise, the signal is unsigned. This parameter is visible only when you select Fixed-point for the Output data type parameter.

Word length

Specify the word length, in bits, of the fixed-point output data type. This parameter is visible only when you select Fixed-point for the Output data type parameter.

User-defined data type

Specify any built-in or fixed-point data type. You can specify fixed-point data types using the following Simulink® Fixed Point™ functions: sfix, ufix, sint, uint, sfrac, and ufrac. This parameter is visible only when you select User-defined for the Output data type parameter.

Set fraction length in output to

Specify the scaling of the fixed-point output by either of the following two methods:

This parameter is visible only when you select Fixed-point for the Output data type parameter, or when you select User-defined and the specified output data type is a fixed-point data type.

Fraction length

For fixed-point output data types, specify the number of fractional bits, or bits to the right of the binary point. This parameter is visible only when you select Fixed-point or User-defined for the Output data type parameter and User-defined for the Set fraction length in output to parameter.

Supported Data Types

PortSupported Data Types

Input

  • Double-precision floating point

  • Single-precision floating point

  • Fixed point

  • Boolean

  • 8-, 16-, and 32-bit signed integers

  • 8-, 16-, and 32-bit unsigned integers

Output

  • Double-precision floating point

  • Single-precision floating point

  • Fixed point

  • Boolean

  • 8-, 16-, and 32-bit signed integers

  • 8-, 16-, and 32-bit unsigned integers

See Also

Constant Diagonal MatrixSignal Processing Blockset
ConstantSimulink
eyeMATLAB

  


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