EXTRACT

Matrix extractor

Block Screenshot

Contents

• `Matrix Extractor`_ +

  • Palette
  • Description
  • Dialog box
  • `Example`_
  • Default properties
  • Interfacing function
  • Computational function
  • `Example`_
  • See also

Palette

• Matrix operation palette

Description

The EXTRACT block extracts some elements from the input matrix. The size of the output depends on the number of rows and number of columns to extract.

The elements of the parameters Lines to extract and Columns to extract specify respectively the indexes of the lines and the columns to be extracted.

The writing of these parameters obeys to the rules of extraction (see extraction), in particular you can give a range of indexes with the colon operator (:).

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.
• Lines to extract A vector indicating the indexes of lines to be extracted. Properties : Type ‘mat’ of size [1,-1].
• Columns to extract A vector indicating the indexes of columns to be extracted.. Properties : Type ‘mat’ of size [1,-1].

Example

A=[1 2 3;4 5 6;7 8 9]
If the "Lines to extract" is [1 2] `and`_ the "Column to extract" is [1 3] then the output is
B=[1 3;4 6]

Default properties

• always active: no
• direct-feedthrough: yes
• zero-crossing: no
• mode: no
• regular inputs: - port 1 : size [-1,-2] / type 1
• regular outputs: - port 1 : size [1,1] / type 1
• 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: extract

Interfacing function

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

Computational function

• SCI/modules/scicos_blocks/src/c/extract.c
• SCI/modules/scicos_blocks/src/c/extractz.c

Example

` `_

See also

• EXTTRI - Triangular or Diagonal extraction (xcos Block)