Array init in formula node

I would like to cut and past in a list of comma seperated numbers and initialize an array of float32. Something like this would work in C.
float32 data[5] = {0,1,2,3,4};
Labview does not like this syntax when using a formula node. I have to do the following instead
float32 data[5];
data[0] = 0;
data[1] = 1;
What is the correct syntax for initializing arrays in lavview using a formula node. I would be amazed if Labview does not have this basic functionality.
thanks in advance
jim bob

labview_noob wrote:
ttt, no one?
Probably because we are using LabVIEW to get away from text based code.
(I don't know if there is a syntax for the formula node, it's been too long. )
If you have LabVIEW 8.0 or higher, you can use matlab like sytax in a mathscript node. Of course you could just paste your list into a string constant and get the values with "spreadsheet string to array".
Message Edited by altenbach on 07-25-2007 12:24 AM
LabVIEW Champion . Do more with less code and in less time .
Attachments:
ArrayFormula.png ‏13 KB

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Array output from formula node with input variable as array size

Hi,
I have created a formula node with an array output called al, but I get an error "you have connected a scalar type to an array with that type".
I declare the output as follows..
float64 al[len_as];
where len_as is an scalar input to the formula node.
It only works when I put a number as.
float64 al[5];
,but I don't know beforehand how many elements I need, so I cannot use this.
Please help! This is so stupid.
Thanks

Don't define your array in your formula node.
Initialize the array as the size you want and pass it in as an input into the formula node.
Are you sure you even need to use a formula node? Can you implement your formula using all native LabVIEW functions?
Message Edited by Ravens Fan on 10-07-2009 11:51 PM
Attachments:
Example_VI_BD.png ‏3 KB

Array Handling in Formula Node

I have attached a simple VI wherein I want to take an input array, look at its size and use the size of the input array as the size of the output array. The output array needs to be declared. I want to be able to use the size of the input array "N" as the size of the output array too. The size of the input array changes dynamically based on my simulation needs. I dont want to modify the size of the array in the declaration every time I change the array size in simulation.
I have tried using b[N] instead of b[10] in the formula node. However LV does not seem to accept this and gives me a syntax error.
Attachments:
Array Handling in Formula node.vi ‏8 KB

AGovi wrote:
However I require to use complicated formulas such as
If a simple formula is easier in G, a complicated formula will also be easier in G.
Actually, it will scale better. Since graphical code is 2D, doubling the code will make it only 1.4x (sqrt2) larger in each dimension, while the formula will double in lenght.
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How can I increment the index of an array in a formula node?

Hi,
I need some help with the formula node. I need an array, that increment every iteration of the code in the formula node. I need it to save amplitudes.
I thought i could do this with i++; i is the variable for my index.
Martin
Solved!
Go to Solution.

Hello,
does it sound well to you ?
@+
Tinnitus
ps: sorry posts mixed
Message Edité par tinnitus le 12-15-2008 03:05 AM
CLAD / Labview 2011, Win Xp
Mission d'une semaine- à plusieurs mois laissez moi un MP...
RP et Midi-pyrénées .Km+++ si possibilité de télétravail
Kudos always accepted / Les petits clicks jaunes sont toujours appréciés
Don't forget to valid a good answer / pensez à valider une réponse correcte
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inc_node.vi ‏6 KB

Array output from formula node

How to get an array output from the formula node.I am trying to use a for loop inside the formula node and want an array output.

You cannot place a For or While Loop inside the formula node.
Here is what the Help Description says about the syntax inside the Formula Node:
Formula Node
Evaluates mathematical formulas and expressions similar to C on the block diagram. The following built-in functions are allowed in formulas: abs, acos, acosh, asin, asinh, atan, atan2, atanh, ceil, cos, cosh, cot, csc, exp, expm1, floor, getexp, getman, int, intrz, ln, lnp1, log, log2, max, min, mod, pow, rand, rem, sec, sign, sin, sinc, sinh, sizeOfDim, sqrt, tan, tanh. There are some differences between the parser in the Mathematics VIs and the Formula Node.
Place on the block diagram
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Note The Formula Node accepts only the period (.) as a decimal separator. The node does not recognize localized decimal separators.
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Array data in formula node

I want to take the Y value (being the amplitute) from the input signal and put it into a formula node. I keep getting the error signal as in the attached VI. Is there a way of seperating the value in labview?
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Formula signal.vi ‏32 KB

Hi Cork,
yes, it's possible! And WTH: you can do it without a formula node with ready-to-use functions!
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

How do I get an array output on a Formula Node?

My problem is simply that I cannot figure out how to get an output on a Formula Node to be an array. Documentation states that "you must declare local arrays and output arrays in the Formula Node" but doesn't say anything more than than. Attempts to put something like "float32 out[100];" for an array output called "out" fail.
If anybody knows how you can do this or even knows if it is possible I would appriciate your help.
Thanks,
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I found a typo in the formula node I was doing that was making the output not be an array. I don't think I was getting the error before but I was going to put together an example VI to attach here and I found it. So, thanks for your help even tho it was a stupid little mistake on my part.

String array into formula node

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I am taking data from SQL, I am getting multiple rows of data for many different devices. I would like to wire the data into a formula node so I can sepearate and sort via script. However, I am getting an error for "Polymorphic terminal cannot accept this data type". Is there a work around? Can I not wire in a string array to a formula node.
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Your own advice is the only and best one.
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Formula node to 2d array

Hey there
I have a problem with my formula Node. I want to recieve a pictue from my camera and generate a 2d-array of the greyscalevalues. That works so far. Now i recieve an array with values between 0 and 4096 (because I have a 12-Bit picture).
Now the problem i have is, that the camera can dim the values, which are bigger than 2048. I tried to fix that problem with a Formula Node. But now i have the problem, that i can't connect the formula node to the intensity graph anymore.
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Hey muks
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Arrays into the fromula node?

Hello,
I am trying to convert my voltages into pressures via the formula node but I am having trouble.
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When I enter the equation into the node it tells me that there is an error on line 1 left brace needed.
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In order to output an array from a formula node, you must declare the array variable.
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HELP: Run-time array dimension in LabVIEW formula node

I need to dimension an array at run time within a formula node as follows:
int32 i,N;
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However, LabVIEW complains "Formula Node: index list expected". On the
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Can't you just use the Initialize Array function outside the formula node and pass that instead?

In formula node how to use array outputs

someone has talked about this. but it is still a problem to me.
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You should be able to declare it using:
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See one of my earlier posts here: http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=135&HOID=506500000008000000EE2C0000&UCATEGORY_0=_49_%24_6_&UCATEGORY_S=0&USEARCHCONTEXT_TIER_0=0&USEARCHCONTEXT_TIER_S=0&USEARCHCONTEXT_QUESTION_0=array+formula+node&USEARCHCONTEXT_QUESTION_S=0
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Attachments:
ArrayFormulaNode.vi ‏23 KB

Can I create array inside formula node

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Shift Register while Indexing Arrays in Formula Node

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I am having trouble using the formula node while indexing my two arrays. I keep getting "NaN" for my output array. I believe the problem lies within my shift register. My guess is that for the first calculation there is not a PreviousAngle so that is why it is giving me "NaN." For the first index I would like the value of the PreviousAngle to be 0. I am new to LabView and unsure what to do.
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Christian Seymour
Solved!
Go to Solution.
Attachments:
Complementary Filter.vi ‏21 KB

The shift register should contain 0 by default since you are using a double [if uninitalized, the shfit register takes the default value of the data type. In this case, the default Double is 0], but you should explicitly initalize the shift register to a default value in most cases.
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Array init in formula node

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