i am using contiki-os to simulate some motes which would have semantic capabilities. As the contiki-os (erbium) is written in C but our semantic libraries are written in java.
can anyone here guide me if it is possible to exploit these libraries in erbium or contiki-os. or i have to rewrite everything from scratch ?
update
just a minor update to the question. is it possible to use java code on the cooja simulator?
Cooja is indeed written in Java.
You can extend or modify Cooja if you need.
You can find out more about Cooja on the Contiki wiki as well as in numerous papres by Fredrik Österlind. Perhaps you should also take a look at Fredrik's PhD thesis "Improving Low-Power Wireless Protocols with Timing-Accurate Simulation", which is mostly about Cooja.
You might be able to use something like this:
http://www.codemesh.com/products/junction/
It appears to have a code generator that takes a java bytecode and create C code from it... but it might also need a runtime library that's platform specific.
With all that in mind, I don't think you will be successful. Most of the platforms are nearly out of space and/or flash by the time you are working with Erbuim; I doubt you'll have resources to process java code somehow.
And if you did get some success from this approach it would probably take a lot of time and effort to do so. With that time and effort you probably could have written the C code to do what you need instead.
Related
Say we have a SystemC model of decade counter and I want to verify SystemVerilog Counter RTL using SystemC model. How can we connect these two in SV/UVM based testbench so as to communicate between them.
Mentor developed a free package called UVMConnect that was developed specifically for the application you are asking about. See https://verificationacademy.com/topics/verification-methodology/uvm-connect. You will need a simulator that supports SystemVerilog and SystemC simulating together, like Questa.
If you're using QuestaSim I think UVM-connect from Mentor is the way to go. When I first used it(4 years ago) it was very buggy and gave the most cryptic segfault errors I've ever seen. But, with help from the Mentor support I managed to overcome them and get stuff done. It should be more stable now, but if you have problems with it don't hesitate to contact Mentor support. They are very responsive.
However, if you're using Cadence tools and/or the e language I think that UVM-ML from Cadence is a much more comprehensive solution. It allows you to connect components written in any combination of languages(SV-SC, SV-e, SC-e) and it has nicer documentation and examples. I understand it's also compatible with all simulators now. You can find it here : http://forums.accellera.org/files/file/65-uvm-ml-open-architecture/
Not sure what Synopsis folks recommend for their tool suite. Maybe someone who used them can offer more information on this. But I'm guessing that both UVM-ML and UVM-Connect could work since their makers claim that they are portable.
And lastly, if you're planning to use SystemC as a verification language(very unlikely but just for the sake of diversity) there is something called UVM-SystemC which is basically a clone of SV-UVM written in C++/SystemC. It's currently in its alpha release and it lacks many features(register modeling, constrained randomization, coverage collection, etc.). It feels a lot like SV-UVM and I think it's a nice toy to play with in your spare time if you can't afford a commercial simulator license. You can find it here http://accellera.org/images/downloads/drafts-review/uvm-systemc-1.0-alpha1.tar.gz
I currently have the need to execute prolog code in an application I am making. I am aware that Apple probably never would allow something like this in the App Store, but that is not the intention either. This is more a private project that will never reach the App Store.
Purpose
In this case prolog is used to describe an object (like for example a telephone) and its properties. The object will be drawn with OpenGL using coordinates specified in the prolog script. The reason for using prolog is that I need the ability to query the program about some of the features this object has, and prolog eases this a lot. Bottom line: I "need" to query a prolog script from my app.
Possible solutions
Embed an already existing implementation written in C. I am unsure if this will even work.
Execute the prolog code on another machine and use the network to query prolog.
It seems that it is possible to run some sort Ruby VM inside the app (shinycocos uses this as far as I understand), could this be used to run one of the Ruby Prolog implementations?
Find some alternative to Prolog. This needs to give me some of the same possibilities I get with prolog.
Sadly, google gives me close to no results at all, so I have a feeling that I might be quite alone on this project. If anyone have any experience or clue at all, I would be very thankful.
Having faced similar difficulties calling prolog code, albeit in a different situation, I'd recommend checking out the castor c++ library. This allows you to write logic paradigm code in native c++ without needing to extend the language at all. As castor is a header only library it is easy to compile wherever c++ is available.
Castor website: http://www.mpprogramming.com/cpp/default.aspx
Half a year later, I would just like to provide some insight on this. I ended up writing a server with an interface to prolog in Java, accepting prolog calls through TCP. It works almost exactly like the live prolog interpreter SWI-prolog (among others) provides, and mostly works quite well. However, it is far from an optimal solution, as you can't call functions from inside prolog. You lose the possibility of having two-way communication.
If I were to start all over again, I would certainly have tried harder to compile one of the pure C implementations for iOS. I gave it a quick go, but my lack of experience stopped me from even removing all of the errors I got. Judging by the fact that you cannot have prolog running as a background process on a unmodified version of iOS as well, some major rewriting would have to be done. Because of this, one might just have to write a new implementation (perhaps inspired by some of the more lightweight ones out there) from scratch to get the perfect solution.
You can download SWI-Prolog's source code and compile it with XCODE for iOS platform. I've never done that, but it's certainly technically possible.
Once you do that, there are a lot of examples on how to run prolog code from C/C++, hence, you will be able to run prolog from Objective-C.
FYI, you can quite easily bi-directionally make calls between Java and SWI-Prolog if you use JPL:
http://www.swi-prolog.org/packages/jpl/
It is also fully re-entrant, so you can instantiate prolog code from java, which in turn instantiates java code etc...
I did this for a number of commercial projects a few years ago when I was required to connect a Prolog based Reasoning Engine to a lot of Java code.
It does use JNI (the Java Native Interface), so you need to be careful about how you compile and link to the native api. Though if you compile it appropriately for each platform you can make it work cross platform. I had it working on OS-X, Windows, Linux & Solaris.
I do not know if this has been tried but there is the possibility to use the combination of NodeJS for Mobile Apps & TauProlog:
https://code.janeasystems.com/nodejs-mobile
https://github.com/JaneaSystems/nodejs-mobile
and
http://tau-prolog.org/
I'm moving away from strict Android development and wanting to create iPhone applications. My understanding is that I can code the backend of iOS applications in C/C++ and also that I can use the NDK to include C/C++ code in Android apps. My question however is how? I've googled quite a bit and I can't find any clear and concise answers.
When looking at sample code for the NDK, it seems that all the function names etc. are Android (or at least Java) specific and so I would not be able to use this C/C++ backend to develop an iPhone frontend?
I'd appreciate some clarification on this issue and if at all available some code to help me out? (even just a simple Hello World that reads a string from a C/C++ file and displays it in an iOS and Android app).
Thanks guys
Chris
Note that I almost exclusively work on "business/utility/productivity" applications; things that rely heavily on fairly standard UI elements and expect to integrate well with their platform. This answer reflects that. See Mitch Lindgren's comment to Shaggy Frog's answer for good comments for game developers, who have a completely different situation.
I believe #Shaggy Frog is incorrect here. If you have effective, tested code in C++, there is no reason not to share it between Android and iPhone, and I've worked on projects that do just that and it can be very successful. There are dangers that should be avoided, however.
Most critically, be careful of "lowest common denominator." Self-contained, algorithmic code, shares very well. Complex frameworks that manage threads, talk on the network, or otherwise interact with the OS are more challenging to do in a way that doesn't force you to break the paradigms of the platform and shoot for the LCD that works equally badly on all platforms. In particular, I recommend writing your networking code using the platform's frameworks. This often requires a "sandwich" approach where the top layer is platform-specific and the very bottom layer is platform-specific, and the middle is portable. This is a very good thing if designed carefully.
Thread management and timers should also be done using the platform's frameworks. In particular, Java uses threads heavily, while iOS typically relies on its runloop to avoid threads. When iOS does use threads, GCD is strongly preferred. Again, the solution here is to isolate the truly portable algorithms, and let platform-specific code manage how it gets called.
If you have a complex, existing framework that is heavily threaded and has a lot of network or UI code spread throughout it, then sharing it may be difficult, but my recommendation still would be to look for ways to refactor it rather than rewrite it.
As an iOS and Mac developer who works extensively with cross-platform code shared on Linux, Windows and Android, I can say that Android is by far the most annoying of the platforms to share with (Windows used to hold this distinction, but Android blew it away). Android has had the most cases where it is not wise to share code. But there are still many opportunities for code reuse and they should be pursued.
While the sentiment is sound (you are following the policy of Don't Repeat Yourself), it's only pragmatic if what you can share that code in an efficient manner. In this case, it's not really possible to have a "write once" approach to cross-platform development where the code for two platforms needs to be written in different languages (C/C++/Obj-C on iPhone, Java for Android).
You'll be better off writing two different codebases in this case (in two different languages). Word of advice: don't write your Java code like it's C++, or your C++ code like it's Java. I worked at a company a number of years ago who had a product they "ported" from Java to C++, and they didn't write the C++ code like it was C++, and it caused all sorts of problems, not to mention being hard to read.
Writing a shared code base is really practical in this situation. There is some overhead to setting up and keeping it organized, but the major benefits are these 1) reduce the amount of code by sharing common functionality 2) Sharing bug fixes to the common code base. I'm currently aware of two routes that I'm considering for a project - use the native c/c++ (gains in speed at the expense of losing garbage collection and setting targets per processor) or use monodroid/monotouch which provide c# bindings for each os's platform functionality (I'm uncertain of how mature this is.)
If I was writing a game using 3d I'd definitely use approach #1.
I posted this same answer to a similar question but I think it's relevant so...
I use BatteryTech for my platform-abstraction stuff and my project structure looks like this:
On my PC:
gamename - contains just the common code
gamename-android - holds mostly BatteryTech's android-specific code and Android config, builders point to gamename project for common code
gamename-win32 - Just for building out to Windows, uses code from gamename project
On my Mac:
gamename - contains just the common code
gamename-ios - The iPhone/iPad build, imports common code
gamename-osx - The OSX native build. imports common code.
And I use SVN to share between my PC and Mac. My only real problems are when I add classes to the common codebase in Windows and then update on the mac to pull them down from SVN. XCode doesn't have a way to automatically add them to the project without scripts, so I have to pull them in manually each time, which is a pain but isn't the end of the world.
All of this stuff comes with BatteryTech so it's easy to figure out once you get it.
Besides using C/C++ share so lib.
If to develop cross-platform apps like game, suggest use mono-based framework like Unity3D.
Else if to develop business apps which require native UI and want to share business logic code cross mobile platforms, I suggest use Lua embedded engine as client business logic center.
The client UI is still native and get best UI performance. i.e Java on Android and ObjectC on iOS etc.
The logic is shared with same Lua scripts for all platform.
So the Lua layer is similar as client services (compare to server side services).
-- Anderson Mao, 2013-03-28
Though I don't use these myself as most of the stuff I write won't port well, I would recommend using something like Appcelerator or Red Foundry to build basic applications that can then be created natively on either platform. In these cases, you're not writing objective-c or java, you use some kind of intermediary. Note that if you move outside the box they've confined you to, you'll need to write your own code closer to the metal.
I have been trying to make work EZSIM with no luck, which is a software to build discrete event simulators in a graphical DOS environment. In this software, my simulator and many others (of the other people in the course I'm taking) don't work, but teacher's simulator (and examples of the downloaded files) does work.
So, I began to distrust of the software.
Do you know any software that resolves the same kind of problems but really works? It will be good if it is free, or I can download an evaluation copy or something like that.
If you don't know any software, do you know any library which might work? Preferably in C#, Ansi C, Java or Delphi.
This may be more than what you're looking for, but check out NS2. It's the standard for open source network simulations, and will allow you to simulate all kinds of network layer behavior.
I've also used JUNG in the past. It's very flexible, although it also doesn't offer much out of the box.
I used Möbius in my computer systems analysis class. It is free for educational use (which sounds like what you're doing). It's a Java GUI which generates C++ code.
The R package queuecomputer. queuecomputer is a computationally efficient method for simulating queues with arbitrary arrival and service times. There is a submitted paper on arXiv describing the algorithm used in the package. Examples can be found within the arXiv paper and the vignette. A web app based on the package is available at https://ace-ebert.shinyapps.io/queue_simulator_mmk/ .
I've worked on a number of products that make use of code generation. It seems to be the only way to achieve both a high degree of user-customizability and high execution speed.
The downside is that we are requiring users to install a compiler (primarily on MS Windows).
This has been an on-going headache, because vendors like MS keep obsoleting compilers, and some users tend to have more than one compiler installed.
We're considering using GNU C, and possibly C++, but even there, there are continual version issues.
I've considered possibly generating assembly language, in an effort to get off the compiler-version-treadmill, but assembly languages are all machine-specific.
Ideally there would be some way to produce generated code that would be flexible, run fast, and not expose us to the whims of third-party providers.
Maybe I'm overlooking something simple, like Java. Any ideas would be appreciated. Thanks.
If you're considering C and even assembler, take a look at LLVM first: http://llvm.org
I might be missing some context here, but could you just pin yourself to a specific version? E.g., .NET 2.0 can be installed side by side with .NET 1.1 and .NET 3.5, as well as other versions that will come out in the future. So as long as your code makes use of a specific version of a compiler, what's the problem?
I've considered possibly generating assembly language, in an effort to get off the compiler-version-treadmill, but assembly languages are all machine-specific.
That would be called a compiler :)
Why don't you stick to C90?
I haven't heard much of severe violations of standards from gcc's side, if you don't use extensions.
And you can always distribute a certain version of gcc along with your product, say, 4.3.2, giving an option to users to use their own compiler at their own risk.
As long as all code is generated by you (i. e. you don't embed your instructions into other's code), there shouldn't be any problems in testing against this version and using it to compile your libraries.
If you want to generate assembly language code, you may take a look at asmjit.
One option would be to use a language/environment that provides access to the compiler in code; For example, here is a C# example.
Why not ship a GNU C compiler with your code generator? That way you have no version issues, and the client can constantly generate code that is usable.
It sounds like you're looking for LLVM.
Start here: The Code Generation conference
In the spirit of "might not be to late to add my 2 cents" as in #Alvin's answer's case, here is something I'd think about: if your application is meant to last for some years, it is going to face several changes in how applications and systems work.
For instance, let's say you were thinking about this 10 years ago. I was watching Dexter back then, but I guess you actually have memories of how things were at that time. From what I can tell, multithreading was not much of an issue to developers of 2000, and now it is. So Moore's law broke for them. Before that people didn't even care about what will happen in "Y2K".
Speaking of Moore's law, processors are indeed getting quite fast, so maybe certain optimizations won't be even that necessary. And possibly the array of optimizations will be much bigger, some processors are getting optimizations for several server-centric stuff (XML, cryptography, compression and regex! I am surprised such things can get done on a chip) and also spend less energy (which is probably very important for warfare hardware...).
My point being that focusing on what exist today as a platform for tomorrow is not a good idea. Make it work today, and surely it will work tomorrow (backward-compatibility is especially valued by Microsoft, Apple is not bad it seems and Linux is very liberal about making it work as you want).
There is, yes, one thing that you can do. Attach your technology to something that just won't (likely) die, such as Javascript. I'm serious, Javascript VMs are getting terribly efficient nowdays and are just going to get better, plus everyone loves it so it's not going to dissappear suddenly. If needing more efficiency/features, maybe target the CRL or JVM?
Also I believe multithreading will become more and more of an issue. I have a gut feeling the number of processor cores will have a Moore's law of their own. And architectures are more than likely to change, from the looks of the cloud buzz.
PS: In any case, I belive C optimizations of the past are still quite valid under modern compilers!
I would stick to that language that you use for generating that language. You can generate and compile Java code in Java, Python code in Python, C# in C#, and even Lisp in Lisp, etc.
But it is not clear whether such languages are sufficiently fast for you. For top speed I would choose to generate C++ and use GCC for compilation.
Why not use something like SpiderMonkey or Rhino (JavaScript support in Java or C++). You can export your objects to JavaScript namespaces, and your users don't have to compile anything.
Embed an interpreter for a language like Lua/Scheme into your program, and generate code in that language.