LabVIEW Idea Exchange

Problem: Many native VIs use the Non-reentrant execution reentrancy setting.

Solution: The vast majority of native VIs should use the Preallocated clone reentrancy setting.

• The native VIs that need to use Non-reentrant or Shared clone are few and far between - they should be identified on a case-by-case basis. Their Context Help and/or Detailed Help should explain why they need to be set to Non-reentrant or Shared clone.

The following is a selection of vi.lib VIs that should use Preallocated clone. This selection is meant to serve as a starting point and is not comprehensive.

Notes:

• This idea is related to: The reentrancy of new VIs should be "Preallocated clone" . They both argue in favour of using the Preallocated clone setting more.
• A significant number of native VIs are already configured to use Preallocated clone, which is great.
• There are curious cases where closely related VIs are set to different reentrancy settings. For example, Color to RGB.vi is rightly using Preallocated clone, while RGB to Color.vi is Non-reentrant. Similarly, Trim Whitespace.vi is rightly Preallocated clone, while Normalize End Of Line.vi - which lives next to it on the String palette - is Non-reentrant.
  • This suggest that the reentrancy setting of some native VIs was chosen haphazardly. This needs to be rectified.
• The fact that so many native VIs are non-reentrant partly defeats LabVIEW's remarkable ability to create parallel code easily. Loops that are supposed to be parallel and independent are in fact dependent on each other when they use multiple instances of these non-reentrant native VIs. When an application uses multiple instances of these native VIs it is as if there are "hidden semaphores" that are added between the various call locations that call these native VIs. This leads to less performant applications (more CPU cycles, longer execution time, larger EXE compiled code size).

Idea Part 1: The menu that appears when right-clicking an input of the Replace Array Subset node should contain Add Input and Remove Input options.

Idea Part 2: The QuickDrop Remove and Rewire tool (Ctrl + Space, Ctrl + Shift + R) should remove unwired inputs of the Replace Array Subset node.

This would be similar to the menus of several other well-loved nodes, such as the Build Array node.

Real-world example

The other day I wrote the following code:

Initially all the inputs of the Replace Array Subset node were wired. Then I realised I had made a mistake, and needed to remove the third-last pair of wires. I deleted the wires. So far so good.

I then selected the node and pressed Ctrl + Space, Ctrl + Shift + R to execute the QuickDrop Remove and Rewire tool, in the hope that it would eliminate the unwired input. It didn't. I then right-clicked the input, hoping to manually select Remove Input. That option didn't exist.

The only option I had was to manually disconnect the last four wires and reconnect them one input above, followed by removing the last input by dragging the bottom edge upwards.

Having to manually disconnect and reconnect wires was a little disconcerting. I wondered: what would have happened if I had made a mistake with say the second input, instead of the third-last input? A lot more manual wiring would have had to be redone.

Notes

• This idea is deeply related to the following idea: Add "Add Element" and "Remove Element" to the Index Array context menu. However, I arrived at it independently during recent real-world work, as described above.

The Wire Multiple Objects Together QuickDrop tool (Ctrl + W) is extremely useful. However, at the moment it has the following limitation.

The other day I found myself writing code like the following.

Naturally I tried using the QuickDrop Ctrl + W tool. However, it produced the result seen below, which is not what I wanted.

The Ctrl + W tool wires each source wire to a compatible (coerceable) destination. In the example above it wires to I32 and DBL destinations indiscriminately.

The desired outcome would be achieved if the tool preferred wiring to destinations that match the source data type exactly, before considering other compatible (coercible) destinations. In the example above, the tool should prefer the DBL destinations. It should wire to the DBL destinations first, before considering I32 destinations.

Notes

• The example above shows 10 wires being wired between the Index Array node and the Replace Array Subset node. The real-world VIs I was programming the other day required wiring multiple pairs of Index Array and Replace Array Subset nodes, some with as many as 30 wires between them. Wiring them manually was a tedious and time-consuming operation.
• This idea is somewhat related to the following idea: Improvement to the QuickDrop Ctrl+W tool: Wire constant to multiple destinations

Hi all,

image processing is not anymore the "tough stuff"/"niche" of the past. Videos are everywhere now, maybe even more than sounds. So functions that handle video should be included in the cross-platform standard labview, at least for the essential functions (reading/writing files with a minimal set of codecs, acquisition of frames through ip or usb for common protocols, conversion between image format for display and processable data). This would attract a lot of young users. It would also jumpstart future developments of labview in the direction of AI.

Thx

Idea: The In Range and Coerce Include upper limit option should be selected by default.

Maybe it's just me, but when using the In Range and Coerce node I virtually always need to have both the Include lower limit and Include upper limit options selected. In approximately ten years of using the node I think I used a different configuration less than five times. It has entered my muscle memory that the first thing I do after dropping the In Range and Coerce node is to right-click it and select Include upper limit.

In my experience this point of view is supported by anecdotal evidence. For example, I have recently seen a large codebase that was rightfully using lots of In Range and Coerce instances. All of the nodes had been left in their default configuration (Include lower limit selected, Include upper limit unselected). However, after inspecting the code carefully I came to the conclusion that the intention was for all of the nodes to perform an inclusive comparison on both sides. This was confirmed by a conversation with the original code author. The author had simply been unaware of the true behaviour of the node (he had assumed it performs inclusive comparison on both ends) and was unaware of the right-click options!