# Extract Triangular Matrix

Extract lower or upper triangle from input matrices

## Library

Math Functions / Matrices and Linear Algebra / Matrix Operations

`dspmtrx3`

## 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.

The Extract parameter selects between the two components of the input:

• `Upper` — 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 therefore identical to the first row of the input matrix. The elements below the main diagonal of the output matrix are zero.

• `Lower` — 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 therefore identical to the first column of the input matrix. The elements above the main diagonal of the output matrix are zero.

## Examples

The ex_extracttriang_refex_extracttriang_ref model below shows the extraction of upper and lower triangles from a 5-by-3 input matrix.

## Dialog Box

Extract

The component of the matrix to copy to the output: upper triangle or lower triangle.

## Supported Data Types

PortSupported Data Types

A

• Double-precision floating point

• Single-precision floating point

• Fixed point (signed and unsigned)

• Boolean

• 8-, 16-, and 32-bit signed integers

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

U

• Double-precision floating point

• Single-precision floating point

• Fixed point (signed and unsigned)

• Boolean

• 8-, 16-, and 32-bit signed integers

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

L

• Double-precision floating point

• Single-precision floating point

• Fixed point (signed and unsigned)

• Boolean

• 8-, 16-, and 32-bit signed integers

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

 Autocorrelation LPC DSP System Toolbox Cholesky Factorization DSP System Toolbox Extract Diagonal DSP System Toolbox Forward Substitution DSP System Toolbox LDL Factorization DSP System Toolbox LU Factorization DSP System Toolbox `tril` MATLAB `triu` MATLAB