LabVIEW parallel for loop and OpenMP

Similar Questions

• 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

• 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).

• 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!

  
  

• How to create parallel tasks using parallel for loops

  Hello

  I'm going to put in place a program that communicates with the six logical controllers and must read the status of the system every 100 Ms. we use OPC datasockets for this, and they appear a bit slow.

  I created a uniform method of comm. for all controllers, and now I find myself this method of programming six times to communicate with each system. I was wondering if it could be done more elegant using the parallel for loop, in which case I program an Exchange once and then six workers running simultaneously. Since a picture is clearer than a thousand words, what I'm asking is:

  Is it possible to replace something like

  

  by

  

  and that for performing these tasks in parallel loop (on different cores / in different threads)?

  I have configured the loop to create instances of the 8 to the compilation, so I would 2 surplus available when running instances if I find that I need an additional system.

  The benefits of the Show method in the second photo for me are:

  * takes less space

  * changes need be made only once

  * less blocks, son and other things makes it clearer what is happening.

  * flexibility of the actual number of tasks running (8 available runtime instances)

  * If multiple tasks are necessary, I need only update the maximum number of instances and recompile, i.e. no cutting and pasting necessary.

  Unfortunately, I don't have these available system yet, so there is no way to test this. Yet, I would like to know if the above works as I hope - unfortunately the help of labview is not quite clear to me on that.

  Best regards

  Frans

  Frans, the parallel for loop will work as expected in this situation. The six tasks will run simultaneously in different threads. What part of the aid could be made clearer?

• When to use the cursor for loop and the cursor (open, fetch, close)

  Hello world
  I have a small doubt about when to use the cursor for loop and when to use the cursor for loop and the cursor (open, fetch, close).
  Well, I'm not the difference between implicit and explicit cursor. So please tell me how I got to know, what to use and when?
  
  
  
  
  Kind regards
  BS2012
  
  Published by: BS2012 on January 29, 2013 12:15

  All SQLs are analyzed, stored and executed as cursors. Thus, you will always use a cursor.

  The problem is that languages, such as PL/SQL, provide different interfaces to interact with the SQL cursor. As the ref, the slider interface, the interface DBMS_SQL slider interface and so on.

  Each of these interfaces offers different features. For example, using the interface DBMS_SQL allows binding dynamics and dynamic recovery. The Ref Cursor interface allows your code PL/SQL pass a handle to a reference pointing to the SQL cursor, to an external client. Etc.

  The fundamental reason for the use of an explicit cursor interface is mainly that you own and manage bulk made extraction output provided by PL/SQL cursor.

  With a cursor FOR , the motor loop of PL/SQL optimize the loop by extracting block a 100 lines both. However, you cannot access this collection in bulk directly inside the loop.

  With an explicit cursor interface, you specify the size of the extraction in bulk via the clause LIMIT , and you set the variable of collection to use. This allows you to use the collection directly variable inside the loop.

  However, the need to do - code manually in bulk collection - rarely occur in the daily programs in PL/SQL. A line of treatment is both slow and not well fits. And even if your bulk code collects lines, these lines must still be processed one at a time in your code. It is much more efficient and scalable rather write SQL code, and make the engine SQL the line of treatment for you.

• Passing an associated variable number between 'for' loops and functions?

  Hello

  I seem to have a problem with the information how variables can be passed between functions and tables.

  I have variable 'capture' put in place as a number.

  grab var: number;

  My intention (I'll do my best to explain) must have a number 'attached' to catch when it is mentioned for the first time in this function, itemClick.

  These must be all relevant tables:

  clickItemArray = [scene_Camp.wood, scene_Ax.ax]

  itemUsableArray = [wood2, ax2]

  ...

  sceneGuyArray = [scene_Camp.guy_Camp, scene_Ax.guy_Ax]

  function itemClick(event:MouseEvent) {}

  for (grab = 0; enter < clickItemArray.length; grab ++) {}

  If (clickItemArray [type] .hitTestPoint (mouseX, mouseY, true)) {}

  addEventListener (Event.ENTER_FRAME, itemRemoval);

  sceneGuyArray [grab] .gotoAndPlay ("guy_Notice");

  trace ("guy_Notice");

  }

  }

  }

  I would like to have the number in place with grab (it would be a 0 or 1, clickItemArray, sceneGuyArray and itemUsableArray) can be passed on to the next function, itemRemoval. I was hoping to use variables I can use the same function for some point clicked on. For example, if the clickItemArray was point 1 (the axe), then sceneGuyArray [Enter] would be = 1, and would play the right frame. Number 1 would be transferred to the itemRemoval function, where he would constantly be listening to sceneGuyArray [1] also (where '1' would have been obtained through the initial 'grab' in the first function) and react accordingly.

  function itemRemoval(event:Event) {}

  for (var grab2:uint = grab; grab2 < sceneGuyArray.length; grab2 ++) {}

  If (sceneGuyArray [grab2] .currentLabel == 'guy_NoticeDone') {}

  removeEventListener (Event.ENTER_FRAME, itemRemoval);

  trace ("cheese");

  }

  }

  }

  I can't get the track works well. I don't know I'm doing something wrong with 'for' loops or the stated case.

  Naturally, help would be appreciated.

  then, in itemClick(), use:

  Grab = itemClickArray.IndexOf (Event.currentTarget)

• Cursor for loop and IN LOOP

  Hi gurus,
  
  I'm going to the table like this:
  
  TEST

  NO      PK
  VALUE

  And I wrote a test cursor procedure to retrieve values such as:
  

  CREATE OR REPLACE
  PROCEDURE test_proc_cursor
    (
      p_no OUT test.no%TYPE,
      p_value OUT test.value%TYPE)
  AS
    CURSOR proc_cursor
    IS
       SELECT no,value INTO p_no, p_value FROM test;
  BEGIN
    OPEN proc_cursor;
    LOOP
      FETCH proc_cursor INTO p_no, p_value;
      EXIT
    WHEN proc_cursor%NOTFOUND;
      dbms_output.put_line(p_no||'       '|| p_value);
    END LOOP;
    CLOSE proc_cursor;
  END test_proc_cursor;

  But, my question is, I have used the simple LOOP in the cursor. Anyone can write the same logic of cursor with all IN LOOP and LOOP FOR it please
  
  Thank you
  
  Published by: user10679113 on January 22, 2009 07:53
  
  Published by: user10679113 on January 22, 2009 07:54
  
  Published by: user10679113 on January 22, 2009 07:55

  Hello

  SQL> DECLARE
    2    p_no    test.no%TYPE;
    3    p_value test.value%TYPE;
    4    CURSOR proc_cursor IS SELECT no,value FROM test;
    5  BEGIN
    6    OPEN proc_cursor;
    7    FETCH proc_cursor INTO p_no, p_value;
    8    WHILE proc_cursor%FOUND LOOP
    9      dbms_output.put_line(p_no||'       '|| p_value);
   10      FETCH proc_cursor INTO p_no, p_value;
   11    END LOOP;
   12    CLOSE proc_cursor;
   13  END;
   14  /
  1       awe
  2       JHKBHNJ
  3       548539
  
  PL/SQL procedure successfully completed.
  
  SQL> DECLARE
    2    CURSOR proc_cursor IS SELECT no,value FROM test;
    3  BEGIN
    4    FOR cRec IN proc_cursor LOOP
    5      dbms_output.put_line(cRec.no||'       '|| cRec.value);
    6    END LOOP;
    7  END;
    8  /
  1       awe
  2       JHKBHNJ
  3       548539
  
  PL/SQL procedure successfully completed.
  
  SQL> BEGIN
    2    FOR cRec IN (SELECT no,value FROM test) LOOP
    3      dbms_output.put_line(cRec.no||'       '|| cRec.value);
    4    END LOOP;
    5  END;
    6  /
  1       awe
  2       JHKBHNJ
  3       548539
  
  PL/SQL procedure successfully completed.
  

  Kind regards
  Dima

• Waiting for timeouts in parallel for loop

  Hello

  I am currently working on a project where I communicate with a number of devices over TCP. This happens at the same time, which is not a problem as long as does not change the number of devices. Now, I want to open my project to support the case with different numbers of hardware devices, which I want to make a loop (read the device of DB information in an array and iterate over all items).

  I read on a single loop parallel execution for, but it seems that the logical cores is a limiting factor for the number of alternative treatments. Unfortunately, I must also take into account delays in communication which translates as the waiting time for each iteration of the loop.

  As you can see I have this creates a lot of idle time that adds up quickly (running with 10 carrots 4 logic devices takes three times the delay to finish without the loop it would not delay time as all connections are pending at the same time.

  I hope someone can direct me to a solution.

  Thank you

  Move the reference VI opened in the first LOOP.

  You use the same reference for all instances.  So wait for asynchronous call will just see one of them finished and the results.  By placing the reference VI open inside your loop, you will have a different reference for each call of your VI.

• LabVIEW RT time loops and logical cores

  The RT 1 stage indicates that you should only use a single timed loop for each CPU whose computer if you want that the loop to be deterministic. When you use a computer with processor containing multiple logical cores within a single processor, can you have a loop timed for all logical cores with them while being deterministic and guaranteed to run at the time?

  If we take the example of a processor like the Core i7 which has a processor but 4 'real' nuclei and an additional 4 via Hyperthreading...

  First, disable Hyperthreading because they don't are NOT actual carrots and won't benefit from the execution of RT.

  The other 4 hearts everything will work loops just as if they were 4 separate processors.

  I don't understand how you can have multiple processors, but one heart, it normally is the opposite, a single CPU (physical processor) to multiple cores (processing units) separate.  The terminology varies, however.

• For loop and access objects by the instance name.

  Hey guys,.

  What I'm trying to do should be very simple, I want to make several non-visible movieclip objects using a loop for.

  Here is what I currently have...

  for (var i: Number = 1; i < 8; i ++) {}

  high [i] .visible = false;

  }

  I have therefore 8 movieclip objects that have names of "high1" instance, "high2", "high3" and so on until 8

  What is the syntax correct for this line of code to make this work?

  high [i] .visible = false;

  Thank you.

  You can use string to instances of the target values, if you use the support rating:

  for (var i: Number = 1; i<8;>

  This ["high" + String (i)] .visible = false;

  }

• 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

• No idea how to loop and add the value to the attribute of the xml node?

  I work on a lot of flattening of project using a watched folder.

  I have a process parent to locate the directory and call a sub-process to flatten PDF files.

  I want to write the directory failed to XML.

  If there are several directory failed locations and if I want to add it to the node, he doesn't let me do.

  If I set the Xpath location like/process_data/outputXML/flattenDirectoryRequestMessage/failureFileLocation[x]/@path it gives me invalid character exception. I use 'x' for looping and incrementing.

  If I do not use the [x]. The directory is overwritten.

  No idea how loop and add all the directories failed to attribute of the xml node?

  I understand that you can not browse the xml code to assign the value at each node. Rather you can assign only one time to the node.

  I realized that it is not possible to do it this way. Then concatenate it as strings, and then attach to the xml once.

• for loops for tons of function

  I wonder how to properly loop these blocks (and those who like them)

  sense (pl. L2. (S1); sense (pl. L2. S2); sense (pl. L2. S3); sense (pl. L2. S4); sense (pl. L2. S5);
  sense (pl. L3. (S1); sense (pl. L3. S2); sense (pl. L3. S3); sense (pl. L3. S4); sense (pl. L3. S5);
  sense (pl. L4. (S1); sense (pl. L4. S2); sense (pl. L4. S3); sense (pl. L4. S4); sense (pl. L4. S5);
  sense (pl. L5. (S1); sense (pl. L5. S2); sense (pl. L5. S3); sense (pl. L5. S4); sense (pl. L5. S5);
  sense (pl. L6. (S1); sense (pl. L6. S2); sense (pl. L6. S3); sense (pl. L6. S4); sense (pl. L6. S5);

  sense (pl. A2. (S1); sense (pl. A2. S2); sense (pl. A2. S3); sense (pl. A2. S4); sense (pl. A2. S5);
  sense (pl. A3. (S1); sense (pl. A3. S2); sense (pl. A3. S3); sense (pl. A3. S4); sense (pl. A3. S5);
  sense (pl. A4. (S1); sense (pl. A4. S2); sense (pl. A4. S3); sense (pl. A4. S4); sense (pl. A4. S5);
  sense (pl. A5. (S1); sense (pl. A5. S2); sense (pl. A5. S3); sense (pl. A5. S4); sense (pl. A5. S5);
  sense (pl. A6. (S1); sense (pl. A6. S2); sense (pl. A6. S3); sense (pl. A6. S4); sense (pl. A6. S5);

  ---

  Sense (MovieClip) is a function that works inside onEnterFrame.

  I actually assume the for loop might look like

  for (I have, I < 0, i ++)

  {the sense (pl. L [i] .s [i]);

  sense (pl. A [i] .s [i]);

  ...

  }

  But I'm terrible at analysis 'for' loops and with a functions a bit scared about 200 + "sense()."

  var a: Array = ['L', 'A'];

  for (var i = 0; i)<>

  for (var j = 2; j)<>

  for (var k = 1; k)<>

  Sense(pl[a[i]+j]["s"+k]);

  }

  }

  }

• 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.