Variable Selector

Fetching a subset of rows or columns from the input data.

blockType: Variable Selector

Path in the library:

/Signal Operations/Signal Management/Indexing/Variable Selector

Description

Block Variable Selector extracts a subset of rows or columns from the input matrix size on on each input port. The number of input and output ports is set in the parameter Number of input signals.

If an element of the index vector refers to a non-existent row or column of the input signal, the block performs the action that you specify using the parameter Invalid index.

If the elements of the indexing vector have a data type Bool, the block performs logical indexing. Select the option checkbox Fill empty spaces in outputs (for logical indexing) to use the parameter Fill values. These values are added to the output signal to make its length equal to the length of the input elements.

Ports

Input

# InN — -th input signal
scalar | vector | the matrix

Details

-th input signal, where – the number of inputs specified in the parameter Number of input signals.

Data types	`Float16`, `Float32`, `Float64`, `Int8`, `Int16`, `Int32`, `Int64`, `Int128`, `Uint8`, `Uint16`, `Uint32`, `Uint64`, `Uint128`, `Bool`, `Fixed`
Complex numbers support	Yes

# Idx — index vector
scalar | vector

Details

Specify a scalar value or vector containing the indexes of the input rows or columns that appear in the output matrix.

Dependencies

To use this port, specify for the parameter Selector mode meaning Variable

Data types	`Float16`, `Float32`, `Float64`, `Int8`, `Int16`, `Int32`, `Int64` \|`Int128`, `Uint8`, `Uint16`, `Uint32`, `Uint64`, `Uint128`, `Bool`
Complex numbers support	No

Output

# OutN — -th output signal
scalar | vector | the matrix

Details

-th output signal corresponding to -the input signal, where – the number of inputs specified in the parameter Number of input signals. The output signal is returned as a scalar, vector, or matrix of the same type, size, and complexity as the corresponding input signal.

Data types	`Float16`, `Float32`, `Float64`, `Int8`, `Int16`, `Int32`, `Int64`, `Int128`, `Uint8`, `Uint16`, `Uint32`, `Uint64`, `Uint128`, `Bool`, `Fixed`
Complex numbers support	Yes

Parameters

# Number of input signals — number of input ports
Real number

Details

The number of input signals as a positive integer. An input port is created for each input signal in the block.

Default value	`1`
Program usage name	`NumInputs`
Tunable	No
Evaluatable	Yes

# Select — the dimension of the input
Rows | Columns

Details

Select the input dimension:

Rows – the block extracts rows from each input matrix;
Columns – the block extracts columns from each input matrix.

The selected input row or column can appear any number of times in any of the outputs or not at all.

Values	`Rows` \| `Columns`
Default value	`Rows`
Program usage name	`rowsOrCols`
Tunable	No
Evaluatable	No

# Selector mode — indexing mode
Fixed | Variable

Details

The type of indexing operation being performed. Set as:

Variable – a vector of length , applied to the input of the Idx port, selects rows or columns of each input to be transferred to the output. You can update the elements of the indexing vector in each sampling period, but the length of the vector must remain the same throughout the simulation period.
Fixed – the Idx port is disabled. A vector of length which you specified in the parameter Elements, selects rows or columns of each input to be transferred to the output. Parameter Elements It is configurable, so you can change the values of the indexing vector elements at any time during the simulation, but the length of the vector must remain the same.

Values	`Fixed` \| `Variable`
Default value	`Variable`
Program usage name	`IdxMode`
Tunable	No
Evaluatable	No

# Elements — indexes of the elements of the output matrix
Scalar / array of real numbers

Details

A vector containing the indexes of the input rows or columns that appear in the output matrix.

Dependencies

To use this parameter, set for the parameter Selector mode meaning Fixed.

Default value	`[1 3]`
Program usage name	`Elements`
Tunable	Yes
Evaluatable	Yes

# Index mode — indexing mode
Zero-based | One-based

Details

Indexing mode. Set as:

One-based – index value 1 refers to the first row or the first column of the input.
Zero-based – index value 0 refers to the first row or the first column of the input.

Values	`Zero-based` \| `One-based`
Default value	`One-based`
Program usage name	`ZerOneIdxMode`
Tunable	No
Evaluatable	No

# Invalid index — error handling
Clip Index | Generate Error

Details

Specify how the block handles an invalid index value. Set as:

Clip Index – truncate the index to the nearest acceptable value and do not issue a warning.

For example, if a signal is applied to the input of the block [64, 4] and for the parameter Select the value is set:
- Rows – the block truncates the index from 72 before 64.
- Columns – the block truncates the index from 72 before 4.
  
  In both cases, the block truncates the index from -2 before 1.
Generate Error – displays an error dialog box and completes the simulation.

Values	`Clip Index` \| `Generate Error`
Default value	`Clip index`
Program usage name	`errmode`
Tunable	No
Evaluatable	No

# Fill empty spaces in outputs (for logical indexing) — option to fill in empty spaces in the output data
Logical

Details

When the elements of the indexing vector have a data type Bool, the block performs logical indexing. Logical indexing can lead to empty spaces in the output data.

Check this box to specify the values that will be added to the output in the parameter. Fill values.

Default value	`true (switched on)`
Program usage name	`FillMode`
Tunable	No
Evaluatable	No

# Fill values — fill-in values

Details

Padding values when the block performs logical indexing.

Dependencies

To use this option, check the box Fill empty spaces in outputs (for logical indexing).

Default value	`0`
Program usage name	`FillValues`
Tunable	No
Evaluatable	Yes