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styrum

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  1. Exactly! To implement an actor in LabVIEW one doesn't need LVOOP! Quite a few "asynchronously communicating modules" producer-consumer design patterns, developed by different people independently from each other including my LabHSM and EDQSM show that very clearly. After all, LVOOP didn't even exist when mine were developed. One can get away with just a cluster in a shift register to access any the data from any action case, but, OK, lets instead make an instance of a "regular" (LVOOP) class and make each action case just call a corresponding method of that class. It will look a little cleaner. The main point of creating an actor is to make an object more than just a bunch of data and methods, to give it a "process", "life", to encapsulate its state and enable it to exchange messages with other objects while having that own "life", i.e. the original Alan Kay's idea about what an(y) object is(should be). If your objects are like that (actors), and you build your application with (out of) them instead of the "regular" (data plus methods) objects, then you don't need all those complex "Gang of Four" design patterns which you indeed better use if you stick with "regular" objects. IMHO the main harm from "THE" Actor Framework is that it scares LabVIEW developers away from the actor model.
  2. Quite a lively 😀 discussion on Slashdot: https://developers.slashdot.org/story/19/07/22/0426201/is-object-oriented-programming-a-trillion-dollar-disaster
  3. I think it is important what exactly we call "OO code". If objects are not simply "dead" combinations of data and methods, but rather have their own "life"/"process", exchange messages with the user, "environment", and other objects the way actors do, react to events, I am all for such "OO code". The "regular/"passive"/"C++/Java/C# style" objects indeed have a very limited use and I agree that the attempts to build large applications using only them by constructing and utilizing complicated inheritance hierarchies and design patterns can lead to a disaster.
  4. 😂He knew what was coming: " I expect some sort of reaction from the defenders of OOP. They will say that this article is full of inaccuracies. Some might even start calling names. They might even call me a “junior” developer with no real-world OOP experience. Some might say that my assumptions are erroneous, and examples are useless. Whatever. " I think we all still can benefit from a more substantive discussion of his particular points rather than from accusations of "not understanding", let alone "calling names" and insults. A "straw man" demagogic trick is no good either. The author opposes not OOP in general or as coined in by Alan Kay, but rather the C++/Java "kind" of OOP, especially inheritance hierarchies and "promiscuous sharing" of state. Neither he advocates "unstructured coding". And the C++/Java/C# style of OOP is not and never has been the only (let alone "best") alternative to "unstructured coding". Actor model is circa 1973. Smalltalk is even older. Statefulness, messaging and concurrent code organization have everything to do with OOP if/when they need to be present in the same program in which you use OOP. Just because you really have to figure out how to implement them in your OOP code then. And, very softly speaking, they are not easily implementable with "regular"/"passive" objects consisting of only data and methods that need to be called from "outside" of the objects themselves.
  5. Some food for thought: https://medium.com/better-programming/object-oriented-programming-the-trillion-dollar-disaster-92a4b666c7c7 Note that LVOOP is indeed the "C++, Java and C# variety of OOP" too, and is taught the same way, complete with "cats and dogs", all the same "Gang of Four" design patterns, S.O.L.I.D (https://scotch.io/bar-talk/s-o-l-i-d-the-first-five-principles-of-object-oriented-design), etc. " The bitter truth is that OOP fails at the only task it was intended to address. It looks good on paper — we have clean hierarchies of animals, dogs, humans, etc. However, it falls flat once the complexity of the application starts increasing. Instead of reducing complexity, it encourages promiscuous sharing of mutable state and introduces additional complexity with its numerous design patterns. OOP makes common development practices, like refactoring and testing, needlessly hard." I don't agree with everything he says, in particular with a definition of state. A variable is a state variable in a reactive (the vast majority of systems/applications and their components built with LabVIEW are indeed reactive and, hence, best modeled as such https://www.reactivemanifesto.org/) module/system/object in my opinion only if the reaction to some event/message (transition, actions that are run in response to the event, and/or target state) can be different depending on the value of that variable. And each object has its own state. The states of all the objects in the program combined constitute the state of the entire program itself, of course. But the very purpose of breaking a program into objects with their own ("isolated") states is to not have to deal with that combined state. The state of each object can and should be "mutable" in a sense, because real life objects indeed change their state with time and that indeed can have an effect not only on themselves but on their interaction with others. It should not be shared explicitly with other objects though, of course. I totally agree with him on that. Personally, I came to developing my LabVIEW applications as collections of asynchronous modules/active objects/actors which are backed by (hierarchical if needed) state machines and communicate with each other only via queued messages long before LVOOP was created, let alone "THE Actor Framework", DQMH, JKI's "State Machine Objects", etc. showed up. Search for "LabHSM" and "EDQSM", they are both circa 2004-2006. Those two templates/toolkits/design/patterns/frameworks of mine, just like some other similar "asynchronously communicating modules" frameworks, have no explicit sharing of state and are closer to the Alan Kay's/Smalltalk idea of objects, where messaging between objects is "The big idea" and where the state of the receiver object (and, hence, the actual code/action/method that will be run as the reaction to a particular message from the sender) is of no business of the sender (now recall Do method in AF's message class and what it takes to decouple actors exchanging such messages)! "Active" objects and actors are not just data and methods, which need to be called externally, by some other methods of some other objects and ultimately by the "God" main loop (well, technically, for active objects as opposed to actors, it is still their methods that are called but those "method calls" are actually just message sending to its process). The main idea is that in contrast to the "regular" OOP, each of "active" objects (actors, modules) has its own "life", in which it reacts to various events, both internal (resulting from its own actions) and external (messages it receives from environment/other objects). It can and often does react to the same event differently, depending on its current state. The reaction consists of running some other actions (which may include sending messages to other objects) and changing its state (transitions). Ideally, it is a true parallelism, not just concurrency, i.e. while communicating with others (within the same physical machine or over the network), it runs in its own thread, process, container, virtual machine or even its own CPU core or an entire real physical machine, because each such object is a "microservice". It is like a complete computer in a sense, just like Alan Kay imagined it. I counted at least three more similar idea "actor frameworks" presented at the latest NI Week and GDevCon. Some of them even use LVOOP :-) Maybe it is time for many other LabVIEW developers to look at the LVOOP and "regular", "passive", single loop/thread (C++, Java, C# style) OOP more critically too. Some more on the topic: https://medium.com/@richardeng/the-object-oriented-schism-9dedbbc3496b
  6. The NI definitions of tag, stream and message/command are given, for example, in this cRIO guide (p. 29): http://www.ni.com/pdf/products/us/fullcriodevguide.pdf
  7. It is indeed amazing and sad how attractive and popular "straw man argument" is. I won't even say anything else.
  8. The matching discussion on NI forums: https://forums.ni.com/t5/LabVIEW/Eleven-Ways-to-Update-an-Indicator-from-within-a-subVI-Their/td-p/3938618
  9. Yes, checking the watchdog queue takes a lot of time (if not most of) in each sender iteration. Please check out a "sequential version" in the latest posts or try putting a Disable structure around those Preview Queue Element nodes in the sender VIs (you will have to stop everything with the stop button on the toolbar of the Main then).
  10. styrum Member ‎06-18-2019 04:17 PM Set Control By Index added. Wow, it is fast! "Speed" calculation in the "sequential" version corrected to count the iterations of the receiver loops. Fastest update of indicator from subVI (5).zip
  11. Ok, OK, my bad, I left Debugging enabled. This is not a commercial app. This is is just some "food for thought", and something to play with, which you would otherwise not have the time to put together yourself. But now you can find some time (much less) to play with it. The goal was to get people to play with it, find flaws, "unfairness", etc. So I am glad that happened so quickly. Here is a version that has debugging disabled plus a "sequential" flavor of the whole thing. Some disclaimers right away: 1. Yes, I deliberately do not count the iterations completed by sender loops but not completed by the corresponding receivers by the time the senders are done, because I do want to count only fully completed "transactions" in evaluating "performance" 2. No, I don't say that lossy and non-lossy methods are comparable "1 to 1" in general context. But for the declared purpose of this particular experiment, updating an indicator in a UI VI, where the user is interested only in the latest value, it is fair to put them "together". Fastest update of indicator from subVI (3).zip
  12. Well, the very point of putting together this code is for people to see the numbers for themselves and that I didn't "cheat" on any of the tested methods to make some look better than others. Their significantly different performance numbers are real. In summary, the main findings are: 1. (Widely known) Passing a control reference to a subVI or a VI running in parallel to the VI where the control(indicator) is located with the purpose of using that reference to update that control/indicator is the worst you can do. 2. (Not so well known) Using "user events" in event structures for the same purpose mentioned and moreover, for implementing asynchronous communications in messaging architectures between "modules", "actors", parallel loops, etc. instead of regular queues and notifiers and now channels is (softly speaking) not a very good idea either from the performance point of view. 3. Even the fastest "channels" are not better than the "good old" notifiers and queues. At least channels give more features and allow to do things impossible before. Which hardly can be said about user events. DQMH is one of the frameworks which rely heavily on such use of event structures one can recall right away. There are others, I bet.
  13. Yes, I know, you wanted to do this some day too. So I did it for you. Just run (and then stop) the Main VI from the attached set (Saved in LabVIEW 2016 32-bit). I suspect (and hope) the numbers will be quite a surprise and even a shock, especially for the fans of one particular method and some very aggressively promoted frameworks which use that method. Fastest update of indicator from subVI.zip
  14. Maybe that will work too (again with a control, not with a constant). But there is no explanation there regarding the type expected as the Conpane (variant) parameter of that Set Conpane method. How do we get that Conpane from a VI we want to take it from before we can feed it to that method?
  15. OK. So OCD is "obcessive compulsive disorder" I figured. Sorry, sickos patients, my native language is not English, but I still know what past participle is and even, for example, when to use past perfect tense in English (How many Americans do?).😋 "Cast Operator: () (programming) A type cast provides a method for explicit conversion of the type of an object in a specific situation. v. cast, casted" (https://english.stackexchange.com/questions/94565/can-casted-be-the-past-tense-of-cast)
  16. For whoever is looking to do anything like this or anything else as far as programmatically changing code in a VI goes, I think I should remind that the best way to find and get a reference to any object you want to mess with on the FP or BD of the target VI is one of "hidden gems", <LabVIEW 20XX>\vi.lib\Utility\traverseref.llb\TRef Find Object By Label.vi
  17. Thank you, Darin! That's exactly what I needed! By the way, what does OCD stand for in this context? BTW2: After calling Change to Constant the constant appears instead of the terminal exactly at the same place the terminal used to be, just as if I right-clicked on the terminal and selected Change To Constant. Well, at least in LabVIEW 2016.
  18. I want to use a Call By Reference or a Start Asynchronous Call node in my TEMPLATE code. Which means I MUST have a type specifier constant (or control) wired to the Open VI Reference. In my CONCRETE code created based on the template code using VI scripting I need to replace the type specifier, or rather the VI which that type specifier extracts the connector pane from, so that the Call By Reference (or Start Asynchronous Call) node can use a new connector pane within themselves instead of the one it has in the template code. Normally (manually) we just drag and drop a VI with a desired connector pane onto type specifier constant or control. But how can we do that (tell it which VI to use) programmatically?
  19. How can I programmatically change the VI which such constant uses (which we just drag onto it normally)? It is a just a "Constant" class according to its ClassName and can not be typecasted to anything else and doesn't seem to have any property or method to set that VI.
  20. So, can you make a tutorial (provide links to info/examples) on specifically that topic: How to make your own project provider, how to add your own items/code to the popup menu on the items in the project editor tree, including your own New..., the same way way Open GDS and AF do? Is this the best place to start? https://forums.ni.com/t5/LabVIEW-Project-Providers/gp-p/bymqyodmkc?profile.language=en What specific troubles did you run into that are not covered there?
  21. In his "Don’t Wait for LabVIEW R&D…Implement Your Own LabVIEW Features!" presentation Darren Nattinger advised to not mess with project providers. So, he didn't give any links to anything on this subject. How did you figure out how to do it? Please provide links/code on how to make your own project provider. Is this the best place to start on this topic? https://forums.ni.com/t5/LabVIEW-Project-Providers/gp-p/bymqyodmkc?profile.language=en Any advice/help/examples you can offer from your own experience making your own project provider?
  22. Here is an implementation of a queued Mealy State Machine. Updated for 2016: https://forums.ni.com/t5/Reference-Design-Content/Event-Driven-Queued-State-Machine-EDQSM/ta-p/3841938 Original LAVA thread: https://lavag.org/topic/4623-simple-event-driven-queued-state-machine-with-front-panel-events-and-a-timer/
  23. OK, so ActiveX still works in Excel 2016. But it is older than .NET and they can still deprecate it in the next version. So, experience on how to communicate with Excel via .NET can become very valuable.
  24. Any idea how to write a 2D array of variants as a whole into Excel sheet using .NET calls? Doing it one cell at a time is apparently not feasible for large recordsets.
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