DSP Blockset

Extract Triangular Matrix

Extract the lower or upper triangle from an input matrix.

Library

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. A length-M 1-D vector input is treated 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.

The output has the same frame status as the input.

Example

The example 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. Tunable, except in Simulink's external mode.

See Also

Autocorrelation LPC	DSP Blockset
Cholesky Factorization	DSP Blockset
Constant Diagonal Matrix	DSP Blockset
Extract Diagonal	DSP Blockset
Forward Substitution	DSP Blockset
LDL Factorization	DSP Blockset
LU Factorization	DSP Blockset
tril	MATLAB
triu	MATLAB

Extract Diagonal

FFT