MATEIG

Block Screenshot

Contents

• Description
• Parameters
• Default properties
• Example
• Interfacing function
• Computational function
• See also

Description

The MATEIG block computes the eigenvalues and the eigenvectors of a square input matrix U. When the decomposition type is set to:

• 1, the block outputs the eigenvalues in a vector form, if the input is a MxM matrix the output is a Mx1 vector.

• 2, the block outputs two matrices. For an MxM input matrix, the first output is a MxM diagonal matrix composed by the eigenvalues, and the second is a MxM matrix where columns are the eigenvectors.

The equivalent of the MATEIG block in Scilab is spec

Parameters

• Datatype(1=real double 2=Complex)

  It indicates the type of the output. It support only the two types double (1) and complex (2). If we input another entry in this label xcos will print the message "Datatype is not supported".

  Properties : Type 'vec' of size 1.

• decomposition type (1=eig values 2=eig values+eig vectors

  To select the form of the output.

  Properties : Type 'vec' of size 1.

Default properties

• always active: no

• direct-feedthrough: yes

• zero-crossing: no

• mode: no

• regular inputs:

  - port 1 : size [-1,-1] / type 1

• regular outputs:

  - port 1 : size [-1,1] / type 2

• number/sizes of activation inputs: 0

• number/sizes of activation outputs: 0

• continuous-time state: no

• discrete-time state: no

• object discrete-time state: no

• name of computational function: mat_vps

Example

A = [1 12 32 ; 21 35 46 ; 70 8 19]
When the "Decomposition type" is set to one the output is y = [-35.649 ; 14.279 ; 76.369]
When the "Decomposition type" is set to two the outputs are:
y1 = [-35.649 0.000 0.000 ; 0.000 14.279 0.000 ; 0.000 0.000 76.369]
y2 = [0.557 0.080 0.349 ; 0.330 -0.922 0.770 ; -0.762 0.379 0.533]

Eigenvalues example: spec([sin(t) 0; 0 t]) = [sin(t); t]

Interfacing function

• SCI/modules/scicos_blocks/macros/MatrixOp/MATEIG.sci

Computational function

• SCI/modules/scicos_blocks/src/c/mat_vps.c
• SCI/modules/scicos_blocks/src/c/mat_vpv.c
• SCI/modules/scicos_blocks/src/c/matz_vps.c
• SCI/modules/scicos_blocks/src/c/matz_vpv.c

See also

• MATSING — SVD Decomposition
• spec — eigenvalues, and eigenvectors of a matrix or a pencil