Include the constant "Tau", the circle constant

[jdunham]

Please add the circle constant tau, to the Math & Scientific Constants palette.  Happy Tau day!  (see more at http://tauday.com/)

[X.]

As far as I can see, it is a DBL constant. There is a type casting bullet on the wire if you try connecting it to an EXT indicator:

So I am just saying that as a DBL constant, it seems to be doing its intended job. What you are asking for is an EXT version of it.

[Darin.K]

You can change the representation of the constants themselves, not coerce them. The EXT versions already exist, they are not as accurate as they could be. I believe this is new in LV10, before you could change representation but not the value. What is good for epsilon should be good for tau, pi and e.

[X.]

Dumb me... I did the following test though:

The results are:

So it still is OK... I think I do things right this time (I checked that with the shorter Pi string, I get a delta of 2. 10E-6), but who knows?

Edit: I noticed the red bullet after the 10^x function. I corrected it with a cast to EXT (not sure what good or bad that makes) and the results are identical...

[Darin.K]

Ah. I ran in LV10, but code was written in LV9. Replacing with fresh constants gives better results. I now suggest when updating these constants that old code gets auto updated to reflect the new value. Getting two different answers in two versions of LV is better than getting two different answers in the same version.

[GregSands]

But given that (Wikipedia):

the decimal representation of π truncated to 11 decimal places is good enough to estimate the circumference of any circle that fits inside the Earth with an error of less than one millimetre, and the decimal representation of π truncated to 39 decimal places is sufficient to estimate the circumference of any circle that fits in the observable universe with precision comparable to the radius of a hydrogen atom

changing those end digits may not make any practical difference to most of us.

[Darin.K]

I completely agree with that argument for physical constants since few are known to better than 5 or 6 sig figs. I completely disagree for mathematical constants which should IMO be defined as accurately as possible since there is no reason not to. Besides, it is very easy to lose half of the precision in a single calculation, so every extra digit can be important. Validation with other programs is also much easier with a well-defined value.

[X.]

Which brings the question: is there a set of VIs out there to perform arbitrary precision arithmetic calculations?

[Darren]

"Pi Multiplied By 2" is already in the palettes.  I am going to advocate that this idea be declined, as it doesn't make sense to add another constant to the palettes with the same value, and you could easily add a "tau" shortcut to Quick Drop for whenever you wanted to drop it.  I wonder how many of the 16 kudos are from people who don't realize the "Pi Multipled By 2" constant already exists?

[jdunham]

Gosh, Darren, such a low opinion of your customers!  Did you read the Tau manifesto?  It's not about adding another constant, this is about changing the world!  You could be part of history!  

Besides, we don't need a new constant, just the ability to correct its appearance, like that silliness that is the Z-1 appearance of the feedback node.  Except in this case it would be a force for good, not for evil. 

[X.]

I think this link is worth checking as well... Oh, but wait a second, Darren, you mean you were... Never mind...