Extract Triangular Matrix

Extract lower or upper triangle from input matrices

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Libraries:
DSP System Toolbox / Math Functions / Matrices and Linear Algebra / Matrix Operations

Description

The Extract Triangular Matrix block creates a triangular matrix output from the upper or lower triangular elements of an M-by-N input matrix. The block treats length-M unoriented vector inputs as an M-by-1 matrix.

Examples

Extract Upper and Lower Triangles from Matrix

Open the ex_extracttriang_ref model. This model shows the extraction of upper and lower triangles from a 5-by-3 input matrix.

Ports

Input

A — Input

vector | matrix

Specify the input as a vector or a matrix of size M-by-N. The block treats length-M unoriented vector inputs as an M-by-1 matrix.

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

Output

U — Lower or upper triangle output

vector | matrix

Extract the lower triangle or the upper triangle of the input matrix. When you set the Extract parameter to:

• Upper — The block copies the elements on and above the main diagonal of the input matrix to an output matrix of the same size. The first row of the output matrix is identical to the first row of the input matrix. The elements below the main diagonal of the output matrix are zero.

• Lower — The block copies the elements on and below the main diagonal of the input matrix to an output matrix of the same size. The first column of the output matrix is identical to the first column of the input matrix. The elements above the main diagonal of the output matrix are zero.

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

Parameters

Extract — Component of matrix to extract

Upper (default) | Lower

Specify the component of the matrix to copy to the output:

• Upper — The block copies the elements on and above the main diagonal of the input matrix to an output matrix of the same size. The first row of the output matrix is identical to the first row of the input matrix. The elements below the main diagonal of the output matrix are zero.

• Lower — The block copies the elements on and below the main diagonal of the input matrix to an output matrix of the same size. The first column of the output matrix is identical to the first column of the input matrix. The elements above the main diagonal of the output matrix are zero.

Simulate using — Type of simulation to run

Interpreted execution (default) | Code generation

Specify the type of simulation to run. You can set this parameter to:

• Interpreted execution –– Simulate model using the MATLAB^® interpreter. This option shortens startup time.

• Code generation –– Simulate model using generated C code. The first time you run a simulation, Simulink^® generates C code for the block. The C code is reused for subsequent simulations as long as the model does not change. This option requires additional startup time but provides faster subsequent simulations.

Block Characteristics

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

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.

Version History

Introduced before R2006a

R2024a: Change in the default value of Simulate using parameter

The default value of the Simulate using parameter is now Interpreted execution. With this change, the block uses the MATLAB interpreter for simulation by default.