Formula Node result of NaN

Hello to all,
I have done a Formula Node with the next formula:B=(2*16/3.14159*(asin(sqrt(V/Ab))-3.14159/4))-(2*16/3.14159*(asin(sqrt(Uoffset/Ab))-3.14159/4));
Ab=3.269.
V is the data entry to the formula node.
Uoffset is the mean of the 100 first values of the data that I obtain it previosly.
I know that I can not do the square of the negative number and the asin I can not do it for values greater than 1 for that reason I don´t put values greater than 3.269 into the V value never and negative values either.
I take this precautions but I obtain several times the output value of NaN I use the entry V for example:0.00061035 could be that the format of the entry it is very extends.
Also when I introduce the same data to this formula, one times I obtain some values in the out and when I execute the subVI with the same data I obtain other values in the out. Said it diferently I obtain different out for the same data in. How it is possible????
The other hand I need to do the integral and the derivate of one array, how can I do it??? And the more important how I can or what I use for the parameter dt of the derivate???
Thanks a lot
Gonzalo De Francisco Ortiz

Hi Gonzalo,
after having a first look: You have a race condition in your code: why do you use a local for the mean value instead of simple wiring?
I think that's the reason for your unexpected results!
Other small items:
- when you use auto-indexing you don't need to provide 'num of iterations' to the for-loop.
- the only difference between the 2 cases is the 'abs'-function used for negative inputs. Just do the 'abs'-function everytime and you don't need the case-structure...
- when testing numbers against zero you can use specialized functions from the comparision palette
Editing:
I attached a changed example in LV8.0
Message Edited by GerdW on 02-01-2007 01:22 PM
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome
Attachments:
FormulaNode.vi ‏20 KB

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