Hi, it looks like your wiki is rather comprehensive. I can clear up some of the issues on it.
The bottom line is that it is possible to build complex, real-time interactive programs, but it often requires using a Java profiler and fixing bottlenecks. Professor Lee and I are in the process of fixing a set of problems for a client (someone who is paying money for this sort of work). Performance tuning can be slow going and requires quite a bit of knowledge. The Towers of Hanoi demo definitely seems slow to me. Perhaps some tuning would help. Drone looks pretty cool! http://drone.ws/index.php?page=about says "Drone is an open source software for digital and interactive arts. It allows the design of realtime signal processing machines for video and audio through a generic data flow interface." Unfortunately, you don't have Windows binaries, so Professor Lee and I can't easily download it. (I'd like to switch to a Mac . . .) I think Ptolemy is very well suited for handling signal processing of audio signals using the SDF domain. We can generate C code for SDF models, and have experimented using The Simple DirectMedia Layer (SDFL: http://www.libsdl.org/) package as output. However, this work is somewhat incomplete, we ran into various issues when we tried to port this code to embedded processors. I believe it worked fairly well on the PC though. Many audio demos will run just fine in real time. See the SDF demos, the applets can be found at http://ptolemy.eecs.berkeley.edu/ptolemyII/ptIIlatest/ptII/ptolemy/domains/sdf/doc/ Video performance is somewhat slower, see the sdf HTVQ demo at ptII/ptolemy/domains/sdf/demo/HTVQ (http://ptolemy.eecs.berkeley.edu/ptolemyII/ptIIlatest/ptII/ptolemy/domains/sdf/demo/HTVQ/HTVQ.htm) Ptolemy II has a pretty nifty interface to Java 3D. Various people outside of the Ptolemy group have been able to quickly create simple models that use Java 3D to illustrate complex behaviour. However, as you saw, the Towers of Hanoi model is slow, and it uses Java 3D. The Furuta pendulum demo and some of the Zeno and Newton's Cradle demos are more useful. To directly answer your time/memory overhead question, it is very easy to build slow large systems using any framework. For example, accessing large arrays in the "wrong" way can cause problems depending on the cache policy. Ptolemy is no different, it is easy to create large, slow models. That being said, a little guidance and a little performance tool use can go a long way. For example, rather than using actors to do trivial things to matrices, it might be better to write a custom actor. BTW - not to start the C++/Java language question, but I find Java much easier to use than C++ and I don't see major runtime perfomance issues in Java as compared with C++. This might be because the areas I work in are not CPU bound tasks. I'll take a look at your wiki and make some updates. _Christopher Christopher Brooks (cxh at eecs berkeley edu) University of California Programmer/Analyst Chess/Ptolemy/Trust US Mail: 558 Cory Hall #1774 ph: 510.643.9841 fax:510.642.2718 Berkeley, CA 94720-1774 home: (F-Tu) 707.665.0131 (W-F) 510.655.5480 (office: 400A Cory) -------- Hi, I am part of a group that develops an open-source (GPL) multimedia platform called Drone. Over the past few years, we have been developing, in C++, a dataflow-oriented, video-only platform. For our next release, we are now targeting a platform that supports different programming paradigms (dataflow, FSM, scripting, etc). We have recently (2 days ago) found out about Ptolemy II and have been studying it alot. We have tried to answer a few questions: https://lethe.koumbit.net/trac/drone/wiki/DevNotes/PtolemyII However, we feel like it would help if someone on this list could give us feedback. Our primary concern is: Can we built complex, real-time, interactive programs with PtII? What is the time/memory overhead of using Ptolemy II? Most of the demos we have found in Ptolemy II have very few entities. The only one with many entities (HanoiTowers.xml) is way too slow, but this may be due to its use of recursion. Thanks, Drone website: http://drone.ws/ Dev site: https://lethe.koumbit.net/trac/drone/ -- J. S. Senécal http://drone.ws --------------------------------------------------------------------------- - Posted to the ptolemy-hackers mailing list. Please send administrative mail for this list to: [EMAIL PROTECTED] -------- ---------------------------------------------------------------------------- Posted to the ptolemy-hackers mailing list. Please send administrative mail for this list to: [EMAIL PROTECTED]
