"Reilly, Timothy (MN17)" <[EMAIL PROTECTED]> writes: > I am new to Ptolemy. I am intrigued by Ptolemy particularly because > if is freely available and I can use it both personally and at work. > I would like to simulate a radar system with it. I am having a > little trouble deciding which domain to use. What I am would like > to do is set up is some sort of a system with a master clock that > fires the transmitter, and delays to simulate ground returns and > system timings that will all be off of a master clock. There will > be digital track loops who will all be synchronous with this clock. > I there a good domain to accomplish this ? I am having a little > trouble figuring out how to do to system timing. I long for a way > to have stuff happen on clock edges as an event.
Sounds like the DE domain to me. You might be interested in VisualSense, a Visual editor and simulator for wireless sensor network system http://ptolemy.eecs.berkeley.edu/visualsense/index.htm The "Antenna Pattern" applet under http://ptolemy.eecs.berkeley.edu/ptolemyII/ptII4.0/ptII4.0-beta/ptolemy/domains/wireless/doc/ might also be of interest. Someone else might have some comments about the specifics. > Also, I have access to matlab/simulink but I am a mathcad user, so I > am kind of the decision point as to what I should invest my time in > learning. I also have access to vissim which came with my last > Mathcad. Will Ptolemy be around for a while and be supported ? > Does it compare well with these other tools ? I know this is like > asking a politician who I should vote for but anyway... Matlab and Simulink are great products. I'm not familiar with vissim and Mathcad. With regard to choosing between Commercial Software and Open Source software, the following general rules apply: Commercial Pluses + Support available + Usually has a more polished UI, the the Ptolemy UI and docs are pretty good Commercial Minuses - Costs money - Can't usually look at the source code to fix bugs Open Source Pluses + Source code available for bug fixes and figuring out how something works + Freely available Open Source Minuses - Usually no formal support - Apparent instability - However, when a corporation goes under the source code can be lost etc. - Usually weaker docs, though the Ptolemy docs are pretty good. There are other pluses and minuses of course. http://ptolemy.eecs.berkeley.edu/ptolemyII/ptIIfaq.htm#simulink says --start-- 2.2 How are Ptolemy II and Matlab/Simulink different? Ptolemy II has very little in common with Matlab, which is a textual, imperative, interactive, scientific programming language. Ptolemy II works with Matlab, thanks to an interface developed by Zoltan Kemenczy and others at Research In Motion, Ltd. See http://ptolemy.eecs.berkeley.edu/ptolemyII/ptIIlatest/ptII/ptolemy/matlab/matlab.htm Ptolemy II has much more in common with Simulink, which is a graphical block-diagram language, originally developed for control system design. Simulink has a rich and expressive model of computation with continuous-time semantics and support for periodic discrete-time signals. Some of its principles have been incorporated in the CT (continuous-time) domain of Ptolemy II, but not all. The CT domain, for example, does not have the notion of "sample time" (which in Simulink provides the periodic discrete-time support) nor the support for algebraic loops. There is also currently no code generation support in CT (in Simulink, this is provided through the associated product Real-Time Workshop). Also, the CT domain has implemented fewer ODE solvers than those provided by Simulink and has a smaller actor library. Ptolemy II and Simulink both support extension of the actor library through well-defined interfaces (in Simulink, this is called the S-function interface). However, Ptolemy II is a more open architecture in that its infrastructure is open source, and the interfaces to the core mechanisms in the software are published and documented. The persistent file format (MoML) is XML in Ptolemy II, which makes it both more verbose and more portable than the Simulink syntax (MDL files). Simulink supports one model of computation, whereas Ptolemy II supports several, and can be extended with new models of computation. Simulink can also be extended, as for example it has been with the associated product Stateflow, which supports state-machine modeling. But in Simulink, the extension is done by defining new blocks using the S-function interface. As such, additional models of computation added this way are second class. For example, they cannot define the model of computation at the top level of the hierarchy, and cannot contain Simulink models within their own components. --end-- Ptolemy II will be around for awhile, but as it is research software, it is likely to evolve over time. We make efforts to keep backward compatibility, for example the nightly test suite runs the 1.0 test models and reports problems. The release notes list backward compatibility issues that are not automatically fixed. Ptolemy Classic is written in C/C++, and was under active development from 1990 until 1997. People are still using Ptolemy Classic, there are a couple of commerical products out that use it in various ways Ptolemy II is written in Java, and started around 1996. At this point, I know of no plans to jump to a different language, but these things sometimes happen. > Also I tried to get into the ftp site to look up the archives but > didn't get in. > > I tried ftp://www.pub/ptolemy/mailing-lists/ptolemy-hackers.archive > in my browser but this didn't work. Please forgive these questions, > I know they probably sound trivial to you all. I'm not sure where the above URL came from, but it is not likely to work - the ftp site has been off line for sometime now. I suspect that we have a bad link somewhere, but a quick search did not turn it up. You can search Ptolemy-hackers in several ways, see http://ptolemy.eecs.berkeley.edu/search/wais.htm Personally, I use Google http://groups.google.com/groups?hl=en&lr=&safe=off&group=comp.soft-sys.ptolemy -Christopher > Regards, > > Tim ---------------------------------------------------------------------------- Posted to the ptolemy-hackers mailing list. 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