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Manual Scilab >> xcos > palettes > Matrix operation palette > MATEIG


Matrix Eigenvalues

Block Screenshot


The MATEIG calculate 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 M-by-M matrix the output is a M-by-1 vector.

When the "Decomposition type" is set to 2, the block outputs two matrices. for an M-by-M input matrix,the first output is a M-by-M diagonal matrix composed by the eigenvalues, and the second is a M-by-M matrices composed by the eigenvectors; the eigenvectors are represented by the columns of the matrix.

The equivalent of the MATEIG block in Scilab is "spec(A)"

Dialog box

  • 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.


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]

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

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



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Last updated:
Wed Jan 26 16:24:42 CET 2011