c++ or java for robotics

Question

I know embedded C is used for micro-controllers along with other languages. but what if the control was from a PC, well I had two possible candidates (java and c++)

Java is simple and easy also Developer friendly when it comes to threading or GUI, but of course C++ is so much better performance (I know computers getting faster, and performance depend on good Algorithms ) but the compilation makefiles, shared-library and cross compiling wastes lots of time caring about technicalities when I should be working on other Important issues.

But still I've faced something like Const references which java doesn't support and force you to use clone() or copying and when that came to arrays it was a giant mess,

NOTE: I'm going to use reverse kinematics and maybe Neural network for pattern recognition. which requires tons of Calculations. but as I said I care also about the whole life cycle of the project (speed of development, performance , user friendliness and quick deployment)

I'm swinging between languages and i'm planning for long term learning process so I don't want to waste that in the wrong language or let's say (without asking) so please help and I hope this question won't be considered subjective but a reference.

cheers

It depends if your robots are going to be cleaning houses or spearheading the invasion of all the major cities. I know if I were writing code to power my squadron of robot ninjas, I'd be using C++. — Moo-Juice, Nov 19 '10 at 13:49
@ismail John Dibling was making a joke... something like: "I ordered my parts off of newegg.com and built my own computer" to which someone would respond "real men build their own gates and work up from there." — San Jacinto, Nov 19 '10 at 14:35
Get a Lego robotics kit, and build some robots. You'll learn more than by asking questions. — MSalters, Nov 19 '10 at 15:29
@MSalters, I already made robotic Arm and control was done through MATLAB, and nowadays i was looking for some long term project and to learn the language that fits our needs is something every body consider when starting a project — Ismail Marmoush, Nov 19 '10 at 21:53

score 4 · Answer 1 · answered Nov 19 '10 at 13:48

Why you eliminated C?

Why do you think java has worse performances then c++? Some things are as good as c++, and it is easy to use java program on different platforms without much hassle.

Just pick the language you feel comfortable and you have most experience with, and go with it.

score 3 · Answer 2 · answered Nov 19 '10 at 13:48

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I wouldnt worry too much about performance at first - write the code in whatever language you feel comfortable in and then refactor as necessary.

You can always use something like JNI to call out to c/c++ if needed, although the performance gap between Java and c/c++ is nowhere near what it was...

answered Nov 19 '10 at 13:48

pauljwilliams

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While I certainly agree with what you're saying, I would add that porting a codebase to a different language gets to be _extremely_ time-consuming after the code reaches a certain size. Choosing the best language for the specifications is very important, but I don't see anything in the very few specs given that suggests that language choice would make a difference. – San Jacinto Nov 19 '10 at 17:19

score 3 · Accepted Answer · edited May 23 '17 at 10:33

Personally I would lean toward C++. Java has a garbage collector, which can put your app to sleep at random. In C++ I have to collect my own garbage, which gives me an incentive to generate less of it. Also C++ allows macros, which I know have been declared a bad thing by Java-nistas, but I use as a way of shortening the code and making it more like a DSL. Making the code more like a DSL is the main way I shorten development effort and minimize introducing bugs.

I wouldn't assume that Java is inherently slower than either C++ or C. IME slowness (and bigness) comes not from how well they spin cycles, but from the design practices that they encourage you to follow. The nice things they give you, like collection classes, are usually well-built, but that doesn't stop you from over-using them because they are so convenient.

IME, the secret of good performance is to have as little data structure as possible (i.e. minimal garbage), and keep it as normalized as possible. That way, you minimize the need to keep it consistent via message-waves. To the extent the data has to be unnormalized, it is better to be able to tolerate temporary inconsistency, that you periodically patch up, than to try to keep it always consistent through notifications (which OO languages encourage you to do). Unless carefully monitored, those make it extremely easy to introduce performance bugs.

Here's an example of some of these points.

score 2 · Answer 4 · answered Nov 19 '10 at 13:55

Depending upon your circumstance, Java is no more quick to deploy than is C++. This mainly boils down to: are you guaranteed the same environment in your testbed that you are in production? With all of the modern additions to C++, there is little cause to suggest that Java is easier on the developer unless you are still new to the C++ language.

That aside, you have performance concerns. Unless it is a real-time system, there's no reason to eliminate any language just yet. If you code your Java intelligently (for instance, do your best to avoid copying objects and creating garbage in the most-used sections), the performance differences won't be seriously noticeable for a compute-bound process.

All told, I think you are focusing too much on textbook definitions of these two languages rather than actual use. You haven't really given any overriding reason to choose one over the other.

that's illuminating thanks man – Ismail Marmoush Nov 19 '10 at 14:01 — Ismail Marmoush, Nov 19 '10 at 14:01

score 0 · Answer 5 · answered Nov 19 '10 at 13:57

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Java is a bit more portable, but as far as I know the only real factor for something like this is personal preference.

answered Nov 19 '10 at 13:57

Maxpm

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score 0 · Answer 6 · answered Nov 19 '10 at 13:58

It would really help if You described Your problem in greater detail.

You are willing to use IK, that might suggest some robotic arm manipulation. What it doesn't say are your real time requirements. If it's going on a class-A production line it'll be hard to get away with garbage collected language.

Java is great. There are some very mature NN libraries (Neuroph, Encog) which could save You a lot of coding time. I don't know of any IK library, but I'm sure there also are at least good matrix manipulation libraries to help.

The Garbage Collection in Java is getting better and better. The latest one (G1) is a lot better than anything else, but even with it the best You can get is soft real time. So You can't expect pause-free run.

On the other hand You also might want to look at some dedicated environments - Matlab toolboxes for robotics and artificial intelligence. I think that would yield fastest prototypes.

If it's going on production than You are pretty much stuck with C or C++.

If you need a pause free run, create less objects. You can write a program which runs for day(s) without a GC if you care enough (very rare) — Peter Lawrey, Nov 19 '10 at 15:33

c++ or java for robotics

6 Answers6