DSP Blockset

Multiport Selector

Distribute arbitrary subsets of input rows or columns to multiple output ports

Library

Signal Management / Indexing

Description

The Multiport Selector block extracts multiple subsets of rows or columns from M-by-N input matrix u, and propagates each new submatrix to a distinct output port. A length-M 1-D vector input is treated as an M-by-1 matrix.

The Indices to output parameter is a cell array whose kth cell contains a one-dimensional indexing expression specifying the subset of input rows or columns to be propagated to the kth output port. The total number of cells in the array determines the number of output ports on the block.

When the Select parameter is set to Rows, the specified one-dimensional indices are used to select matrix rows, and all elements on the chosen rows are included. When the Select parameter is set to Columns, the specified one-dimensional indices are used to select matrix columns, and all elements on the chosen columns are included. A given input row or column can appear any number of times in any of the outputs, or not at all.

When an index references a nonexistent row or column of the input, the block reacts with the behavior specified by the Invalid index parameter. The following options are available:

• Clip index -- Clip the index to the nearest valid value, and do not issue an alert.

• Example: For a 64-by-4 input with Select = Rows, an index of 72 is clipped to 64; with Select = Columns, an index of 72 is clipped to 4. In both cases, an index of -2 is clipped to 1.

• Clip and warn -- Display a warning message in the MATLAB Command Window, and clip as above.
• Generate error -- Display an error dialog box and terminate the simulation.

Examples

Consider the following Indices to output cell array:

• {4,[1:2 5],[7;8],10:-1:6}
  

This is a four-cell array, which requires the block to generate four independent outputs (each at a distinct port). The table below shows the dimensions of these outputs when Select = Rows and the input dimension is M-by-N.

Cell	Expression	Description	Output Size
1	4	Row 4 of input	1-by-N
2	[1:2 5]	Rows 1, 2, and 5 of input	3-by-N
3	[7;8]	Rows 7 and 8 of input	2-by-N
4	10:-1:6	Rows 10, 9, 8, 7, and 6 of input	5-by-N

Dialog Box

Select

The dimension of the input to select, Rows or Columns.

Indices to output

A cell array specifying the row- or column-subsets to propagate to each of the output ports. The number of cells in the array determines the number of output ports on the block.

Invalid index

Response to an invalid index value. Tunable.

Supported Data Types

• Double-precision floating point
• Single-precision floating point
• Fixed point
• Custom data types
• Boolean
• 8-, 16-, and 32-bit signed integers
• 8-, 16-, and 32-bit unsigned integers

To learn how to convert your data types to the above data types in MATLAB and Simulink, see Supported Data Types and How to Convert to Them.

See Also

Permute Matrix	DSP Blockset
Selector	Simulink
Submatrix	DSP Blockset
Variable Selector	DSP Blockset

Multiphase Clock

N-Sample Enable