for loop speed

Similar Questions

• Have different conditions for loop start and stop

  I do a VI when a circle is moving on an image control and its movement is decided by programming, but also by the user. I have programmed the speed of the circle as a vector which turns (using a rotation matrix) when a certain condition is met. This condition is dependent on the position of the circle and direction as well as other entries. The tricky thing is I want to that when the rotation condition is met (true), the rotation continues until the angle of the vector is equal to the original angle (when the condition became real) + / variable x.

  So my question is how do I program a piece of code that once activated, will run until a stop (depending on the State of vector early in the race) condition is reached. As it should be when the VI is on, I can not put a while loop inside an another while loop. Online help mentions also conditional for loops, but it isn't available in my version of LV (8.2)

  The correct solution is a state machine with a case inside a single while loop structure. Based on the need to use one of the several cases and move on to another matter as necessary using a state variable (for example, an enum) in a registry change. One of the cases should be slowed down and not do much except maybe controls survey.

  There are a lot of models.

  Do not hesitate to contact a simplified example of your code and help you.

• 3D table organization fomr a 1 d array in a for loop

  Hello-

  I am currently using a program OR opening multiple files (http://zone.ni.com/devzone/cda/epd/p/id/818). As a side note, I noticed that the files are automatically organized by name once records are returned from the Subvi. Will be called BxCy where x is a number and y is a number to two digits (e.g., B2C34) and within each file, I load a 1 d table which I extracted the files, I am loading.

  I want to do is organize the output so it has the structure of

  Page C1

  Line B1 [(table 1 d)]

  Line B2 [(table 1 d)]

  ...

  Line Bn [(table 1 d)]

  Page C2

  Line B1 [(table 1 d)]

  Line B2 [(table 1 d)]

  ...

  Line Bn [(table 1 d)]

  and so on.

  My first question is that I'm not 100% sure that the file names will be organised by name in the lu multi-fichier VI so is there someone who can check it out? Second, even with what I would like to know if there are effective methods to achieve this. Should I just use two tables index to classify based on their number of anc C B? This seems to slow down and I saw on other positions the function array reshape could speed up the process but I'm not sure how to proceed. I don't have access to the structures of inplace (I don't know if I just forgot to install this module, or if it was not included in my subscription LabVIEW).

  The program that I joined is in LabVIEW 2009 SP1 and I'm on a Windows 7 64-bit machine.

  Thank you in advance!

  J

  • You did not include the subVIs. Please do.
  • Never convert a path to a string, unless you do something specific OS. Use 'strip path' work on the name of the file as strings, then convert back to a path using "build path" if necessary.
  • To create a 3D tables 1 d array, you need two stacked FOR loops. Pages in the loop external and rows in the inner loop and outoindex in the output in loop tunnels. You will automatically get a 3D Board.
  • It might be much easier to use the "list of files" with a motif of "B * C *" for example. Is the number of the page always 1 and the numbers of two line numbers (padded with a zero not significant as appropriate)? In this case the sorting will be correct.

• Parallel for loop 2D table

  Hello

  I don't have any experience with parallel for loops, so I need your help.

  Goal: To do a calculation (average, average) on the rows (or columns) table 2D as quickly as possible. The calculations are independent of each other and I would get a table 1 d with the results.

  I read a few posts on parallel for loops and I would like to find an example for my trivial problem, but I can't.

  Could you help me, it is possible is improve it the effectiveness of the calculation on lines with parallelism in LabVIEW? and it is, could you post an example how to do?

  Thank you

  If the speed issues, do not write your own "average." First of all, it already is in the range of statistics, but then you must be inline your average VI or do the calculation explicitly (as shown below). the size of the array never changes for the duration of the loop, it seems redundant to get the size of the array on each iteration.

  Here's what you could do.

  

  On my bench, it's much faster than the use of 'mean.vi' of the palette. Average a overhead, Subvi (1) (2) needs to get N with each call and (3) is also an unnecessary error checking.

  (Sorry, I have 32 processors, so the number of instances is set a little high. Modify if needed).

• should I i38? I have FF, and I do not use ie8 im or outlook. Are there other reasons, I need ie8? I want to remove for better speed.

  should I i38? I have FF, and I do not use ie8 im or outlook. Are there other reasons, I need ie8? I want to remove for better speed. Edit

  Sorry, but you can't permantely delete IE (I wish we could) beacause its part of the core of the Windows operating system.

• parallel processing: for loop taking place

  Hallo,

  I have a loop 'for' runnin on this system: LabVIEW2009, windows7, intel i7.

  I wonder if and how I can tell to LabVIEW that he would be allowed to run different iterations of the loop at the same time (concurrently) on my processor with 8 cores.

  Now, it will execute the next iteration when it ended the previous, even one so is there no dependencies in iterations.

  I want to give a 'ownership' of the loop, which means that it can be "unfolded" for parallel execution.

  Thank you

  Pier

  pop up on for loop and select "configure interation Prallelism."

  Activate it.

  Wire a certain number to the new 'P' of entry to specify how many processors to spread it everywhere.

  Ben

• for loop in formula node does not

  Hello

  I; m trying to use for loop in the node of the formula, but it is does not work. I want the output (y1) product value in certain range (a and d, and of course one is smaller than d). I ' do not use primitive labview since a and d are keep changing (both are variable). I tried to put "return 0;" after the y1 equation but the error popup.

  The issue of the loop works not because it gives the last value (I average would be ""). It does not begin with an (initial) value.

  Please help me how to solve this problem...

  Pls ignore other variables not used in the equation. Thank you!! A lot

  Your code works.

  

  But why you use loop?
  You get the last value, so you can get it in a single step with x correct;

  Also why you say that can not use primitives?
  If you use wire instead of terminals or local variable States values constant.

  Y1, y1_2, y1 3 is the same values calculated differently.

  

• parallel for loops does not

  Hello.

  I'm learning the multi - thread programming. To start, I use "parallel for loops" and I was surprised that it does not work. One - thread loop work a few times faster (depending on settings) that multi - thread. I don't know why, and it is my request to correct my Vi to work properly.

  Lenovo, G580, Windows 7, 64-bit computer

  Intel Core i7 3632QM
  Ivy Bridge
  Specification Intel (r) Core i7-3632QM CPU @ 2.20 GHz
  Package (platform ID) Socket 988 B rPGA (0x4)
  Number of hearts 4
  Number of threads 8

  LabView 2011.

  Altenbach says:
  

  Gibbon wrote:

  What was 'strange' behavior?  In "linia dluga" when inside the loop is on '1' of the "spreed up' between one and multi-fil is about 3 times, when I put it in '20' this grow to 6.2. It was strange form me, becourse I expect a similar value.

  A parallel FOR loop has an overhead for parallelization (split the problem, then go back the results, etc.). If the code is very fast, the overhead is proportionally larger. If the Subvi takes a long time to complete, the overhead of parallelization is insignificant. It is often not worthwhile to parallelize the loops with a very simple and fast code.

  Gibbon wrote:

  Altenbach - I have another question if you can help me - how did you "seconds relative high resolution." VI "? -I want to say how did you know that there is this 'vi '. And thanks a lot for your modyfications.

  You can find it in vi.lib\utilities. It is well known.

  Maybe not well known enough!  the 'Hidden gems' package adds to your palattes.  It has also been considered by a nugget of the community

• For loop runs with the value of N unwired

  In this case will be a loop run connected to the loop N worthless? I have seen a few examples of the loop for run without a certain number of times set to be ran wired or for example a size of table or something like that.

  PauldePaor wrote:

  Here's a program I am and as you can see the image that the program runs without the loop N being wired. The program will run without problem

  As everyone else has said, you don't have to plug something on N.  If you wire up a table for loop for input "auto-index", the loop for will run automatically the smaller table size.

  Perhaps an example will help:

  

  This makes a loop on my table size (in this case, long of 5 elements).  On the edge of the loop for which resembles [] brackets, indicates that it is auto-indexé.  The loop should go through each item one at a time (1, then 2, then 3, then 4, then 5).

• Préallouée VI environment in paralleled for loop

  Hello

  I searched a bit and couldn't find that everything about this specific issue.

  If I have a Subvi in a parallelized for loop and the Subvi is set upon reentrant preallouee clone, the Subvi register also several characteristics of memory depending on the number of loop iteration For? My specific application is a Subvi containingvibration Analytisis screw using the previous data in their spread and filters.

  Thank you!

  
  

• For loop creates 1 d data table

  Hello, I am building the circuit below, and I'm running into a lot of problems with the loop, creating a table 1 d of data from certain types of data such as the ERROR OUT and the VISA NAME of RESOURCE. I understand why it does this, but I only need the last value in the table (the value of the last iteration of the loop for). This is true for me for the error, resource name of visa, and I was thinking of using the Boolean value that indicates when the for loop.

  Is there a simple way to extract the last value in the table 1-D so that it is correct to pass along trails, VISA and ERROR type?

  You actually create a block diagram, not a circuit.  A circuit is an electrical system including devices and wires.

  If you right-click on the tunnel and choose disable indexing, then you get the value of the last iteration rather than a 1 d table.

  I recommend you watch the LabVIEW tutorials online
  LabVIEW Introduction course - 3 hours
  LabVIEW Introduction course - 6 hours

• LabVIEW parallel for loop and OpenMP

  Hello:

  It's just a curious post, I just learned about OpenMP and I found that OpenMP helps you to parallelize loops in c about the same way that you can use the loop For parallel in LabVIEW.

  The loop For Parallel LabVIEW is being implemented under the hood using OpenMP? Or is it just a coincidence?

  No, it is not implemented LabVIEW parallel for loop under the hood using OpenMP. You might be interested to read this article on modern developments in the LabVIEW compiler architecture. Specifically, in this case, it's the DFIR technology discussed here that facilitates parallel for loop transformations.

• For loop within a while loop

  I have for loop within a while loop... admission to the for loop N comes from the VI selection... the while loop I a condition essentially statement it stops just after to finish all the iteration in loop...

  Entrance to the N loop is bascially driven by a local variable... that's the problem Iam having:

  When I press the Start button to run the program... regardless of the output of the select VI is gives the N of the for loop, then the loop starts and then ends in place... and when the output of the select statement takes a different value (the N of the loop for) loop not work until I restart the program again... What can I do so that the for loop runs again for another value of N, the RUN program button is enabled.

  1. clean your diagram.  Style guides suggest keep the pattern of a single screen.  With a little effort, I was able to get your DB less than 1600 x 1000 pixels.

  2 then I can see (some) it happens all at once. This thing does nothing?

  3. local variables can lead to race conditions.  Output in Angle position may be a race condition, although is probably not what you wanted to do.  What does the wired local time at the moment present terminal meter? (Ooops! Two controls with the same name - which can be quite confusing as well!)  If you need or want two components of façade having the same text, use the legends.  Make the labels is different so the comic is more readable.

  4. having more than one Dequeue function on the same queue will lead to unpredictable results.  When an item is removed, it is removed from the queue and is not accessible to any other Dequeue function.  In parallel loops, you have no way of guessing which Dequeue will seize any particular element.

  5 use Boolean reverse instead of Select with wired False to true and true cable at the entrance to false entry. Better, just make the case of forgery in the structure of the case within the for loop the real deal. No required reversal.

  6. I was not looking for to determine the logic of the code within the structure of this case. It seems I could have posted a much simpler way to do this several weeks ago.

  7. use multiply from the Digital Palette rather than a node form multiply by 4 or 1.8. Uses less space BD and is much easier to read.

  8. as has been suggested, learn how to work the machine architecture and the State of producer/consumer.  They can make your life much easier.  Do not try to convert immediately to these models.   It's too much bite to at some point.  Learn how they work first.  Make a few simple examples.  Then rewrite this program in this format.  Probably faster than fixing what you have now.

  Lynn

• For loop tunnel exit "Last value" output of default values

  Salvation OR community,

  Today, I came across a probem of LabVIEW stange. A tunnel of release of "Last value" to a for loop back the default values instead of the last real value. The code is below:

  

  Below as screenshots of probes 44 and 45.

  

  

  When the probe 44 contains al the data (all the planks are present (and the correct "Testrack Module" is used)) probe 45 is empty.

  I already tried to remove the complete thread and it rewire. The result was the same.

  However, I also tried to use registers with shift instead of the tunnels and the code works now (see below for the code).

  

  The used version of Labview is 2013 SP1.

  I hope you can help,

  Tim

  Edit: If the images are too small, you can drag it to a new tab, and they become the original size.

  Tim,

  My first assumption: the because the loop never executes as you pass an empty array to an entry of automatic indexation.

  Another option, which is difficult to see in the screenshot: are there two entries of tunnels over the probe nr 42?

  Norbert

• FOR loop does not update the local Variable

  I am newer to labview, and I can't wrap the head around why not a habit of local variable to update in the code if it updates on the dashboard. Anything im missing?

  Assume that you are talking about the local variable of the 'State of the cell. The terminal updates every 500ms in the small top loop, the local variable indicates simply that the indicator and thus updates also.

  The problem is "dataflow" and you need to familiarize yourself with the concept!

  Once the while loop starts, the local variable is reading and inside the loop begins. Most likely, the local variable is read before it is updated in the small loop, so most likely returns the value of a fade on the first iteration of the while loop. Now the small loop continues to go twice per second for about five seconds. Only after the loop FOR (and everything else inside the while loop) completed, the while loop will go to the next iteration, date on which the local variable is read once more, this time with the last value of the last for loop iteration of the previous iteration of the while loop.

  In summary, the local variable updates very well, it's just that the code does not read the new value around most of the time.

  Your VI is full also potential competition conditions caused by the over-use of the local variable. You need to respect the proper execution order by eliminating local variables.

  So what is the solution? Hard to say without knowing what the VI is supposed to do. Most likely, you will need to remove the inside OF the loop and use it outside while loop for everything.