LabVIEW

cancel
Showing results for 
Search instead for 
Did you mean: 

Elliptic integral in LV a different result

Solved!
Go to solution

Hi All,

In LabVIEW I found a different result for the elliptic integral of first kind.

 

For example if I put input k= 0.994673

LV give a result K(k)= 4.01

 

All other routines, this is an example:

https://keisan.casio.com/exec/system/1180573454

 

Give a result K(k)= 3.6656...

 

Someone could explain me why?

What is the correct result?

 

0 Kudos
Message 1 of 6
(670 Views)

Hi Mal,

 

maybe you should also attach the VI you are using to calculate the integral…

(Many of us prefer older LabVIEW versions, so you might "Save for Previous" to provide your VI for LV2019 or so in case you use a recent LabVIEW version.)

Best regards,
GerdW


using LV2016/2019/2021 on Win10/11+cRIO, TestStand2016/2019
0 Kudos
Message 2 of 6
(638 Views)

Hi,

Attached code.

 

Best regards 

0 Kudos
Message 3 of 6
(613 Views)
Solution
Accepted by topic author Mal123

It seems LabVIEW defines the k slightly differently.

 

altenbach_0-1693671924407.png

 

 

You get the correct values if you square the input as follows.

 

altenbach_0-1693671741198.png

 

altenbach_0-1693672807188.png

 

 

I am not familiar enough with the details of the parameter conventions or who is more "right". 😄

 

Message 4 of 6
(583 Views)

LabVIEW probably should have called the input terminal "m" instead of "k". (see here)

 

altenbach_0-1693672331723.png

 

 

Note that Matlab also uses "m" (i.e. k²) as input, but names it correctly. (details).

 

Message 5 of 6
(576 Views)

Dear Altenbach,

Thank you very much, I was going crazy, 

I was deceived by the fact that the second kind result was about the same number rounded.

 

Best regards 

 

 

0 Kudos
Message 6 of 6
(545 Views)