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2020 Visual Bug? Single Input Compound Arithmetic Not Allowed With Error?

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I don't fully understand what triggers this condition.  But I've seen times when the Compound Arithmetic node with one input, and the error data type showing a broken wire, but the VI can be ran.

 

Single Input Error.png

 

The VI does actually run, but the wire shows it is broken.  Attached is the code saved in LabVIEW 2020 that reproduces the error.

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Single input Compound Arithmetic seems crazy to me (but I see why you did it).  I'm not surprised that it's buggy.

I would just replace it with an unbundler.

"If you weren't supposed to push it, it wouldn't be a button."
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I often use single input Compound Arithmetic to perform inversion - either numeric (1/x) or boolean NOT.   It's more compact than the native functions so it fits between wires when I place it inline between subvi's that use all 4 standard outputs and inputs (a.k.a. gazottas and gazintas).

 

No insight on the visual bug, I've never had it happen.

 

 

-Kevin P

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Yeah I hope the demo VIs shows why you might want a feature like this, even though it seems an odd choice at first.  There are probably a dozen other ways to accomplish something similar, but this seemed logical to me.  Yes the unbundle would work just fine, but it is a bit smaller on the BD and I couldn't see a reason why it shouldn't work.

 

Also it probably shouldn't surprise anyone, but the old band-aid of Always Copy fixes this graphical issue.

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@Hooovahh wrote:

Also it probably shouldn't surprise anyone, but the old band-aid of Always Copy fixes this graphical issue.


For we Newbie's, can you please explain what "Always Copy" means?  I don't think I've (probably because I'm not quite as inventive) the problem you're describing, but I also occasionally "squeeze" functions in between wires, so might want to avail myself of these nifty ideas, but don't know where to find the band-aids ...

 

Bob Schor

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@Bob_Schor wrote:

@Hooovahh wrote:

Also it probably shouldn't surprise anyone, but the old band-aid of Always Copy fixes this graphical issue.


For we Newbie's, can you please explain what "Always Copy" means?  I don't think I've (probably because I'm not quite as inventive) the problem you're describing, but I also occasionally "squeeze" functions in between wires, so might want to avail myself of these nifty ideas, but don't know where to find the band-aids ...

 

Bob Schor


Check the Application Control >> Memory Control Palette

 

Always Copy will make a data copy of what is contained on the wire.

 

Snap20.png

 

mcduff

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Yeah I was keeping a list of times the Always Copy fixed a weird bug, or edge case.  But after a while I realized keeping a list of the primary feature of a function seemed silly.

 

https://forums.ni.com/t5/LabVIEW/TDMS-Write-cannot-accept-datatype-what-s-going-on-here-then/m-p/293...

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Can someone from NI confirm this bug?  Assign a CAR?

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