averages in an array

[bdarroux]

Hi,

I would like to do an average.

Now, I read some values (voltage) and I put them in an array. I read the values N times, and I add the old values with the new ones.

At the end, I divide by N all values. The average is done.

My problem is that I write the new values  (N) after the N-1 reading. My program did not remplace old values by the addition.

How can I specifie that I want to start to write the new values at index 0 of the array of new values.

Thanks fo your helping.

BD.

[AndrewAlford]

How are you building the array? What do you mean by "after the N-1 reading..". If you post your code or a picture of the block diagram it would help.

[bdarroux]

barrette_new is the array of new values

I read the element at the index i of the two array. I add this two elements, and I remplace the value of the array barrette_old with this new value.

I repeat this loop N times.

Here, the elements of barrette_new are added at the end of barretete_old, and I have, at the end of the program the N array of barrette_new in barrete_old.

Thanks,

BD.

[Dennis_Knutson]

There is no picture. If you clicked the Insert an Image button and your image was on your local pc, unless your pc is a public web site, that won't work. Use the attachment button below instead.

Instead of adding individual array elements and then doing a divide, just build the array and use the Mean function on the Analyze><athematics>Probablility and Statistics palette.

[bdarroux]

Sorry for this mistake 😞 I did nt see the attachement buton o_O.

BD.

[Dennis_Knutson]

Why are you using so many local variables? If you're going to use a for loop for anything, a shift register should be used and you should also use the auto indexing feature of a or loop instead of the Index Array functions. Every time you use a local variable, you make a copy of the data and that's not effecient.

[DFGray]

Do you need to use a loop?  The arithmetic operators are polymorphic and they do take arrays as inputs.  In addition, LabVIEW includes VIs do simple things like an average (not to mention complex things like non-linear minimization).  Do a search for average and you will find a couple of options (depending on what version of LabVIEW you are using).

[bdarroux]

hi,

I will try your both solutions, and tell you if I resolv my problem.

tanks,

BD.

[bdarroux]

I reduce the number of local variables and I use a register shift, but it did not works, where is my mistake?

I send you the picture of my code: I would like to do an average of AVERAGES (local variable) times with a signal I acquire with DAQ card. After treatment, I got an array: BARRETTE_NEW. I add all values with an other array: BARRETTE_OLD. I do this operation AVERAGES times.

BARRETTE_NEW and BARRETTE_OLD are initialized to 0.

Did I use coorectly the shift register?

Thanks,

BD.

[bdarroux]

Hi, I solved my problem. Thanks very much for your helpful answers.

BD