calculating execution time

[JJJOndae]

I'm trying to test the execution time on a subvi before I implement it a larger design into another VI.  It's testing the time difference between using a mathscript node and the labviews native math functions.  However, I am not able to get any kind of time delay using the tick count function. Attached is my code, I'm using labview 8.2

[RavensFan]

Your code is not attached.  I'm sure the native LabVIEW functions will be much quicker.  But if the calculation is quick enough, you might not see a difference.  Try doing the calculation repeatedly with a For Loop a thousand times, or a millions times, to magnify the time of execution.

[JJJOndae]

ooops I'm sorry, here it is attached.  I've tried running the for loop for over 10,000,000, and can see a delay in executing physically, but it will not calculate.  I can not figure out why.

Message Edited by JJJOndae on 05-23-2010 09:14 PM

[Timmar]

Formula execution will be far less than 1msec. 2344324786343 - 2344324786343 = 0

For this sort of testing you will need to call the function multiple times, start with 10,000 and keep increasing until you can see the differences.

Drop a for loop into the centre of your sequence structures.

[Timmar]

Try this instead, and yes, there is a significant difference.

[JJJOndae]

Thank you for the help, but could you somehow save the file in a version that will allow me to open?  I'm using 8.2 (ancient I know :D)

[Timmar]

Oops, My Mistake.

Labview applies constant folding and optimises a fair bit of this code out.

[Timmar · Accepted solution]

lv 8.2

[JJJOndae]

Wow, this works absolutely perfect.  That is a genious idea what you did there, I don't think I would have ever thought of that.  And I can see now my mathscript will execute much quicker.  Thanks so much!!

[Dennis_Knutson]

Message Edited by Dennis Knutson on 05-23-2010 09:13 PM