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  1. Past hour
  2. Can you share some examples if available?
  3. Hi Jeremy, Would you please update http://lavag.org/bbq to direct to this post? It still directs to 2018 BBQ. Thanks, Fab
  4. Today
  5. So this is where it gets trickier. Intrinsically the kernel-client protocol is geared around sending strings to the kernel and by and large getting strings back. This makes sense if one thinks the client is essentially a terminal with a keyboard, a screen and a human. So trivially you can express the data to be sent to Python from LV as an assignment statement "x=3.141592654" and have that executed on the kernel and it will create variables in the kernel's namespace - but it's hardly efficient if what you want to do is send a moderate sized 2D array of floating point numbers over. I think the solution is to implement a pair of Comm[1] objects to send and receive custom messages[2] in which data can be encoded in a more efficient way and used to manipulate the globals() on the Python side and request specific variables to be sent back to Python. I've had a look around at various 'binary json' serialises and liked the look of ubjson[3] the most (ideally I'd implement the Python pickle algorithm in LabVIEW, but that didn't look fun!). That would solve the how to encode the data for transfer part of the problem. The actual mechanics I think will involve a CommunicationsChannell LabVIEW class that has methods to squirt the python needed to create the Comm objects at the kernel end, deal with the kernel requesting to open it's side of the communications back to the LabVIEW and then methods to send arbitary LabVIEW data and request Python data and map it back to LabVIEW types. Finally it will need to implement comm-open, comm-close, and comm message types - but they're basically easy given the class hierarchy that already exists for messages. All of which is great, but I'm running out of Easter vacation, about to hit the summer exams and I'm the departmental exams officer so have negative free time for a few months! [1] https://jupyter-notebook.readthedocs.io/en/stable/comms.html [2] https://jupyter-client.readthedocs.io/en/latest/messaging.html#custom-messages [3] http://ubjson.org/
  6. thats quite the hidden gem🎅 🦄
  7. Thank you for your kind reply. I totally understand about while loop mechanism. It's helpful for me.
  8. PS: Did I mention that the design of these things was arcane and bad? Yes? Ok. 'Cause it's true. I have a long list of lessons I hope NXG learns.
  9. XControls work just fine... if you dance with them the way they were intended. *head bang* If you don't want data to be saved, one way is to not put it in the State data. If you only need the data in the facade, add a shift register. But if you need it lots of places, put a global unique ID (GUID) in the XControl's state data, something that never changes after creation, and create an LV-2 style global with a lookup table from the unique ID to the data. You can create GUIDs on any LV OS using: LabVIEW 2017\resource\Framework\Providers\API\mxLvGenerateGuid.vi Changing the state shouldn't cause the VI to need to be saved unless it needs to be saved. So, yes, sure, in the IDE in a directly called VI, yes, changing state dirties the VI. But obviously that doesn't happen in a built app. AND, importantly, it doesn't happen in the IDE for any dynamically loaded VI (unless you are adding the 0x1 flag to track changes, in which case you get what you requested). If you're loading the hosted VI into a subpanel, that means you're working with it by VI Reference. So load it using Open VI Reference (without the flag) and the problem of being prompted to save should go away.
  10. Yesterday
  11. OK so the connection to a Jupyter notebook works, great. I can define a variable in the notebook and read its value in LV. Now how do I send something to the notebook from LV? 🙂
  12. That solves part of the problem, but not all of it. Using the Convert State for Save ability lets you stop writing volatile state information to disk, but it doesn't stop LabVIEW from thinking that the host vi (i.e. the one you've put the XControl into) requires saving. That happens as soon as you toggle the state changed boolean in the action cluster. You need to have an entirely separate means of storing volatile, per instance, state and then not touch the state boolean in the action cluster unless you really do mean to record a change that would require saving. I've been using variant attributes on a variant stored in an LV-2 style global, but I guess one could use 1 element queues, or even, gods forbid, a global variable! That said, I;ve just realised that I ought to have coded the Uninit Ability on my XControls to clean up the per instance variant attributes when the host vi goes out of memory....
  13. @Yassamina BERKANE The answer is the same as it was in 2006: dequeue and concatenate. A ragged 2D array is not (and never will be) meaningful in LabVIEW. Because the compiler cannot guarantee that you're going to add arrays of all the same size to the queue (you might be doing that, but it cannot be proven from code because refnums can be shared all over the place), any attempt to ask for all the queue elements in one array will have them each wrapped in a cluster. If you dequeue and concatenate, you can build a 2D array yourself.
  14. Last week
  15. Isn't there an optional ability VI you can add to an XControl that will modify the state before saving? It says it's specifically for this purpose.
  16. Aww, that's a shame. It would still be nice to get it added to LabVIEW though; then it will be possible to use this framework without adding a big dependency. New data types sound exciting though; are you allowed to say what they are? (A hint at least?)
  17. LogMAN

    LabVIEW Memes

    We'll grow into it eventually 😋
  18. ShaunR

    LabVIEW Memes

    am I doing this right?
  19. How to overlap 2 images along overlapping area in labview? I have tried many methods but I am not getting desired result. mask.vi
  20. I think so. Well. I know so but I'm unsure of the mechanism since it is an xControl on a VI that is loaded in a sub-panel of another xControl (if that makes sense-it's nested). When exiting, the host VI (loaded in the sub-panel) wants to be saved. I can stop it by not updating the display state of the xControl on the loaded VI host, but then the facade doesn't update properly. Additionally, it doesn't seem to be every time; just sometimes which is proving to be a barrier to finding a work-around. If it's not loaded in the xControls sub-panel (even a normal subpanel), then it all works as intended. I have, since, thought of a couple of things to try, but it'll have to wait until I can get round to it again. Amen.
  21. That may be a while - but the package file itself in the top of the thread.... Edit: Thinking about, because I'm dependent on the ZMQ bindings which are not available on the NI Tools network, I'm not sure I can put this package (and the SHA-256) library on the NI Tools network either - so it will always need to be installed from manually downloaded vipm files.
  22. Let us know when it is posted on VIPM's package list.
  23. Ok, bit of Easter holiday coding today. Version 1.1.0 should allow connections to remote and already running kernels (well it does for me), and will only issue kernel shutdown messages if it started the kernel itself. To connect to a remote kernel, you can either manually fill in a cluster of port numbers etc, or simply paste the json from the connection file or (if you have an existing front end to the kernel) do: from ipykernel.connect import get_connection_info print(get_connection_info()) If starting kernels on another machine, remember to tell them to bind to an IP address that isn't localhost e.g. ipython kernel --ip=u.x.y.z and make sure the firewall will let the ports through.
  24. I'm way above my head here, but are you saying that in principle the "clustering" of multiple control is just a convenience trick or is that bringing advantages (such as access to class properties via property nodes) that would be lost otherwise (defining a facade with multiple controls NOT bundled into a cluster)? Of course, what's missing for this to be even practical, is more flexible way of grouping objects in LabVIEW (that is, one that allows moving things within a group). Just to put my questions in context, I have developed a simple (well, relatively) way of adding a tip strip to graphs so that long plot names can be read without having the legend size explode. I was contemplating migrating it to a QControl, but the layout of a Graph (due to its accessory panels) can be quite random, and if everything (graph and tip strip) is put into a cluster, the problem I was raising above would potentially ruin the day in some UI cases.
  25. FragRz I didn't mean the private Method you referred to , I was talking about the when you have LV open and go to Tools -> Compare -> Compare VI Hierarchies... Dan
  26. Sorry, I should have explained more clearly what it means that the method is private. In short, private methods are not officially supported - they may not have documentation, they may not work, or they may even have unexpected side effects - just like in your case.
  27. Well , since I installed the evaluation version of LV2018 i played around with the Compare VI Hierarchies tool , it actually does everything I need ... But , be cautious using it at first when Creating a Report , it did the webpage report just fine , when I tried to create a Word Doc it failed , AND , deleted everything in the directory it was supposed to save the Word doc in , luckily I was using the Temp directory so it wasn't a big issue , in fact on a second try at it , it deleted the Temp directory too , not just the contents... As I said I am using the evaluation version , so , maybe something is wrong with my install. Dan
  28. Hmm, there was a problem I had there but I thought the version I packaged had fixed it. My current development version should find that path - but it depends quite a lot if you have multiple Pythons installed on your machine. BAsically there doesn't seem to be a bullet proof way of getting the correct path in Windows.... That's a sensible idea - it's going into the development code. That's largely a result of the test client being mainly aimed at debugging the protocol and for testing message handling rather before moving on to code to more tightly integrate LabVIEW programs with the remote kernel. That said, I'm in the process of adapting the client to allow different methods of locating and connection to the kernel and that will include suppressing the kernel shutdown message on exit. I'm also (very slowly) working on an implentation of a LabVIEW universal-binary-json serialiser/deserialiser with a view to creating some custom ipython messages for transferring binary data efficiently between LabVIEW and Python. The idea is that the LabVIEW client would create message handlers at the Python end that would allow LabVIEW data to be pushed directly into the Python namespace or to request python data to be sent back to LabVIEW. Don't hold your breath though, the day job comes first...
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