Table Of Contents
Array Subset (G Dataflow)
Returns a portion of an array starting at a specified index and containing a specified number of elements.
array
An n-dimensional array of any type.
This input also accepts clusters containing a single array, such as waveforms. This input changes to waveform when the data type is a waveform.
Data Type Changes on FPGA
When you add this node to a document targeted to an FPGA, this input has a default data type that uses fewer hardware resources at compile time.
index
First element, row, column, or page to include in the portion of array you want to return.
If index is less than 0, the node treats it as 0. If index is greater than or equal to the array size, the node returns an empty array.
Relationship between index Inputs and array Dimensions
For multidimensional arrays, index inputs correspond to row-major order. Thus, the first index corresponds last dimension of the array input, and the last index corresponds to the first dimension of the array input. The following table shows the relationship between four index inputs and the dimensions of a 4D array input.
| index Order | Corresponding Dimension in array Input | index Name |
|---|---|---|
| 1 | 4th | volume index |
| 2 | 3rd | page index |
| 3 | 2nd | row index |
| 4 | 1st | column index |
waveform
The waveform whose array of y values you want to use in this operation. This input becomes available when you wire a waveform to array.
length
subarray
The portion of array starting at index and containing length elements. This output changes to waveform subset when the input data type is a waveform.
Data Type Changes on FPGA
When you add this node to a document targeted to an FPGA, this output has a default data type that uses fewer hardware resources at compile time.
waveform subset
Subset of the provided waveform based on the parameters you specify. This output is only available when the input data type is a waveform.
When to Use Index Array Instead of Array Subset
When you need to extract a subarray that is an entire row or column of the array input, use Index Array. To extract a subarray using Index Array, wire only index and length inputs for the dimension(s) you want to extract. For example, if the input to Index Array is a 2D array and you wire only the row input, you extract a complete 1D row of the array. If you wire only the column input, you extract a complete column of the array. If you wire the row input and the column input, you extract a single element of the array. Each input group is independent and can access any portion of any dimension of the array.
Where This Node Can Run:
Desktop OS: Windows
FPGA: DAQExpress does not support FPGA devices
Web Server: Supported in VIs that run in a web application