lu (MathScript RT Module Function)

LabVIEW 2012 MathScript RT Module Help

Edition Date: June 2012

Part Number: 373123C-01

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Owning Class: linalgebra

Requires: MathScript RT Module

Syntax

l = lu(a)

[l, u] = lu(a)

[l, u, p] = lu(a)

Description

Decomposes a matrix into upper and lower triangular or trapezoidal matrices using Gaussian factorization.

Examples

Inputs

Name Description
a Specifies an m-by-n matrix.

Outputs

Name Description
l If you specify [l, u, p] = lu(a), l returns the lower triangular matrix with 1 on the diagonal such that l*u = p*a. If m > n, l returns the lower trapezoidal matrix. l is an m-by-min(m, n) matrix.

If you specify [l, u] = lu(a), l returns a matrix equal to p'*b, where b is the lower triangular matrix with 1 on the diagonal. If m > n, l returns a matrix equal to p'*b, where b is the lower trapezoidal matrix with 1 on the diagonal. l is an m-by-min(m, n) matrix.

If you specify l = lu(a), l returns the strict lower triangle of the lower triangular matrix and the upper triangle of u in the same matrix. If m > n, l returns the strict lower triangle of the lower trapezoidal matrix and the upper triangle of u in the same matrix. l is a matrix of the same size as a.
u Returns an upper triangular matrix such that l*u = p*a. If m < n, l returns an upper trapezoidal matrix. u is a min(m, n)-by-n matrix.
p Returns an m-by-m permutation matrix such that l*u = p*a. The LU-factorization of p'*a thus works without row interchanges.

Details

The following table lists the support characteristics of this function.

 Supported in the LabVIEW Run-Time Engine Yes Supported on RT targets Yes Suitable for bounded execution times on RT Not characterized

Examples

A = [-6, 17; 3, 8]
[L, U] = lu(A)
B = L*U