Floating Point Equal? primitive

[candidus]

Everybody knows the problem:

We need custom VIs to compare floating point values using a tolerance.

 

I just discovered something via scripting:

 

The Floating Point Equal? primitive which does exactly that.

 

 

Can anyone imagine why it is missing from the standard palette?

It's in LV since version 8.0 ...

 

 

FloatingPointEqual_LV80.vi

[ShaunR]

Nice find

 

It would be nice if the tolerance had a default value so for most use cases we didn't have to specify it.

[Dan DeFriese]

Can anyone imagine why it is missing from the standard palette?

It's in LV since version 8.0 ...

My imagination is limited so I selected the context help - it sends you to '(Incomplete) Beta Function'. So I'd guess that either it dropped off someone's radar at NI or there was a problem with the implementation and someone forgot to remove it (and dropped off the radar ever since!).

[Jordan Kuehn]

Nice find

 

It would be nice if the tolerance had a default value so for most use cases we didn't have to specify it.

Especially if the default tolerance would automatically adjust according to the type of floating  fixed point number wired into it. (misread and thought the title said fixed point.  would still be cool if it could automatically adapt to fixed point inpuits).

[Darin]

Makes it even easier to implement my idea:

 

http://forums.ni.com/t5/LabVIEW-Idea-Exchange/quot-Almost-Equal-quot-functions-for-Float-comparisons/idi-p/1446480

[candidus]

Makes it even easier to implement my idea:

 

http://forums.ni.com/t5/LabVIEW-Idea-Exchange/quot-Almost-Equal-quot-functions-for-Float-comparisons/idi-p/1446480

 

That's odd. There's an existing well kudoed idea and an existing primitive but nothing happens... NI, where are you?

[mje]

There are multiple "correct" ways to check for near equality and perhaps the implementation as it stands is not what NI wanted to endorse as the way of doing things. As in many things, often the best implementation depends on context. Just my guess.

 

I think it's neat the primitive exists, but don't see it as a major loss that the functionality isn't on the native palette.

[Mr Mike]

An unofficial response: avoid this primitive.  It was requested by a group within NI and it turned out they didn't need it halfway through its development.  In a lot of cases it can create a compile error.  In some cases it will cause a crash on save.  The author says that it was never thoroughly tested (so don't expect IEEE 754 conformance!) and that bug reports for it are rejected since it was never officially released (not even for internal use).

 

This is a prime example of digging around in LabVIEW and finding fool's gold instead of actual gold.

[candidus]

This is a prime example of digging around in LabVIEW and finding fool's gold instead of actual gold.

 

Well, that's why I asked about it. Thank you! Nevertheless I think there should be done something about it:

Either implement the primitive properly or remove it entirely. Since it was never released this should break nobody's code.

[hooovahh]

This is a prime example of digging around in LabVIEW and finding fool's gold instead of actual gold.

Dang, but my sincerest thank you for addressing this.

[Mr Mike]

Dang, but my sincerest thank you for addressing this.

 

No problem.  If it makes you feel better, I kudo'd the original idea.