DSP Blockset    
Cholesky Solver

Solve the equation SX=B for X when S is a square Hermitian positive definite matrix.

Library

Math Functions / Matrices and Linear Algebra / Linear System Solvers

Description

The Cholesky Solver block solves the linear system SX=B by applying Cholesky factorization to input matrix at the S port, which must be square (M-by-M) and Hermitian positive definite. Only the diagonal and upper triangle of the matrix are used, and any imaginary component of the diagonal entries is disregarded. The input to the B port is the right-hand side M-by-N matrix, B. The output is the unique solution of the equations, M-by-N matrix X, and is always sample-based.

When the input is not positive definite, the block reacts with the behavior specified by the Non-positive definite input parameter. The following options are available:

A length-M vector input for right-hand side B is treated as an M-by-1 matrix.

Algorithm

Cholesky factorization uniquely factors the Hermitian positive definite input matrix S as

where L is a lower triangular square matrix with positive diagonal elements.

The equation SX=B then becomes

which is solved for X by making the substitution Y = L*X, and solving the following two triangular systems by forward and backward substitution, respectively.

Dialog Box

Non-positive definite input
Response to non-positive definite matrix inputs. Tunable.

Supported Data Types

To learn how to convert to the above data types in MATLAB and Simulink, see Supported Data Types and How to Convert to Them.

See Also

Autocorrelation LPC
DSP Blockset
Cholesky Factorization
DSP Blockset
Cholesky Inverse
DSP Blockset
LDL Solver
DSP Blockset
LU Solver
DSP Blockset
QR Solver
DSP Blockset
chol
MATLAB

See Solving Linear Systems for related information. Also see Linear System Solvers for a list of all the blocks in the Linear System Solvers library.


  Cholesky Inverse Complex Cepstrum