# eigsort (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

ev = eigsort(a)

ev = eigsort(a, b)

[evec, evdiag] = eigsort(a)

[evec, evdiag] = eigsort(a, b)

ev = eigsort(a, order)

ev = eigsort(a, b, order)

[evec, evdiag] = eigsort(a, order)

[evec, evdiag] = eigsort(a, b, order)

Legacy Name: `eigs`

## Description

Computes eigenvalues and eigenvectors for real or complex square matrices. eigsort(a) solves the standard problem ax = lambda*x. eigsort(a, b) solves the general problem ax = lambda*bx. Out of all possible eigenvalues and eigenvectors, LabVIEW returns only six according to the order you specify.

Details

Examples

## Inputs

Name Description
a Specifies a square matrix whose dependent matrices are also square.
b Specifies a matrix of the same size as a. If you specify b, LabVIEW calls the qz function.
order Specifies how to determine which eigenvalues and eigenvectors to compute. order is a string that accepts the following values.

 'LM' (default) Sorts the eigenvalues by magnitude from largest to smallest. 'SM' Sorts the eigenvalues by magnitude from smallest to largest. 'LR' Sorts the eigenvalues by real part from largest to smallest. 'SR' Sorts the eigenvalues by real part from smallest to largest. 'LI' Sorts the eigenvalues by imaginary part from largest to smallest. 'SI' Sorts the eigenvalues by imaginary part from smallest to largest.

## Outputs

Name Description
ev Returns six eigenvalues of a or the generalized eigenvalues of a and b. ev is a vector.
evec Returns a matrix of six columns whose columns are the normalized eigenvectors of a or the normalized generalized eigenvectors of a and b.
evdiag Returns a 6-by-6 matrix with the elements of ev on the diagonal.

## Details

LabVIEW does not solve for the off-diagonal Jordan structure associated with repeated roots. If repeated roots to eig(a) or eig(a, b) exist, LabVIEW might ill-condition evec artificially.

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

A = rand(100);
C = eigsort(A)

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