Limitations

• Ptolemy II 10.0.1 Limitations Page - Limitations found after release.
• Ptolemy II Bugzilla

Version 10.0.1 has the following limitations:

Release Limitations

• The gzipped tar file of Ptolemy II source files with Unix line endings (ptII10.0.1.src.tar.gz) requires GNU tar or WinZip. Solaris 2.5.1 tar will fail to untar this file with a checksum error because the pathnames are longer than 100 characters.

  Note further that some of the .class names are longer than 31 characters, which may cause problems when downloading zip files on the Macintosh and using Stuffit.

• The documentation for custom actors used in demonstrations is not included in the release. The source code for the custom actors can be found in the source download.
• If a URL ends with #in_browser, then Ptolemy II will invoke the User's web browser. Unfortunately, this does not always work, especially under Windows. The workaround is to exit Netscape and let Ptolemy II start up your browser for you.
• Web Start does not work very well if the pathname to the vergil.jnlp file has spaces in it. The workaround is to place your Ptolemy II tree in a directory that does not have spaces in the path name if you plan on using Web Start.
• If your user library contains actors that are not present in vergil, then you may see a dialog or dialogs asking if you want to skip these elements. This could happen if you had developed custom actors and put them into your user library and these custom actors are not present in the release. The work around is to click 'Skip Element' and continue with the start up.
• Web Start issues:
  • The Matlab Wireless demo fails under Web Start. The problem is that the Matlab .m file cannot be found.
  • The JAI Adaptive Median model does not work under Web Start - the repaired image might be corrupt. The reason is that it uses the JAI acceleration libraries, which Web Start does not load.
  • Viewing a pdf file may bring up a blank window along with the pdf file. Running the code generator may bring up a blank window while the java or javac processes are running.
  • Some of the links on the GR domain instructions page might not work under Web Start because the files they refer to are not present.
  • Under WebStart, in the HOC ParallelExecution and SpontanousSources models, it is not possible to look inside the ThreadedComposites.
  • In the ExportToWeb version of the HOC Case, the Documentation icon is not active.
  • The ReadStdIn demo fails under Webstart. (This model now has an annotation about this). The error is:

    	      ptolemy.kernel.util.IllegalActionException: The file 'System.in' does not have any data.
    	      in .ReadStdIn.LineReader
    	      at ptolemy.actor.lib.io.LineReader._openAndReadFirstTwoLines(LineReader.java:344)
    	      at ptolemy.actor.lib.io.LineReader.fire(LineReader.java:225)
    	    

  • Running Ptango SmartRoom under WebStart brings up a partial page?
    1. Go to https://ptolemy.berkeley.edu/ptolemyII/ptII10.0/ptII10.0.1/org/ptolemy/ptango/demo/SmartRoom/SmartRoom/
    2. Click on "Launch" to download the Web Start files.
    3. Run the model
    4. Click on the annotation to open http://localhost:8078/room
    5. Note that the page is only partially rendered. The problem is that the style sheets common.css and berkeley.css are not present.
    Generating WebStart on a laptop works. Probably the issue is with the css files.
• Limitations in demonstrations
  • The SDF Image Compression HTVQ demo does not display any images.
  • The Pthales FFT demo fails to generate an image.
  • The Ptango Exception demo does not restart if there is a JavaScript error.
    1. $PTII/bin/vergil org/ptolemy/ptango/demo/Exception/Exception.xml
    2. Hit run
    3. Type in nonsense text, hit return
    4. The model finishes. It should restart.
• Limitations in demonstrations that are documented using annotations in the model.
  • Continuous CarTracking should be run using View->Run so that the user can change the fault parameter.
  • The DE Bouncer demo: If the user drags the bouncing icon, it no longer bounces.
  • Some of the Ptango demos such as EPlus70 and TemperatureSensor require EnergyPlus and are not likely to run under WebStart bcause the BCVTB_HOME environment variable need to be set.
  • The Ptango OccupancyAlert and SensorAndrew demos requires a password, but even with the password it fails to run, the message is:

    	      ptolemy.kernel.util.IllegalActionException: Unable to login to XMPP server.
                  in .OccupancyAlert.XMPPGateway
    	      Because:
    	      SASL authentication DIGEST-MD5 failed: not-authorized
    	    

    with the server up, the message is:

    	      ptolemy.kernel.util.IllegalActionException: Error evaluating expression: "http://localhost:" + port + "/simulator#in_browser"
    	      in .OccupancyAlert.link
    	      Because:
    	      Error evaluating expression: WebServer.getAttribute("deployedPort").getToken().intValue()
    	      in .OccupancyAlert.port
    	      Because:
    	      The object on which method "getToken" is invoked on is null, but the method is not found or is not static.
    	      in .OccupancyAlert.link
    	      Because:
    	      Error evaluating expression: "http://localhost:" + port + "/simulator#in_browser"
    	      in .OccupancyAlert.link
    	      Because:
    	      Error evaluating expression: WebServer.getAttribute("deployedPort").getToken().intValue()
    	      in .OccupancyAlert.port
    	      Because:
    	      The object on which method "getToken" is invoked on is null, but the method is not found or is not static.
    	      at ptolemy.data.expr.Variable.validate(Variable.java:1532)
    	    

  • The Ptango UCBPower and UCBPowerAnalyzerServer demos does not work under WebStart because the Ptolemy configuration used to display models under WebStart does not support exporting to the Web.

Limitations in the Class Mechanism

There are several known problems:

• Several higher-order-components will not work inside class definitions. (ModalModel, several Continuous actors, etc.).
• Name collisions can occur when adding objects to base classes whose names collide with objects in derived classes. Auto naming should look through the derivedList for name conflicts.
• Propagation of changes to a base class is very slow in Vergil. If there are more than just a very few instances or derived classes, interactive editing is not practical. As a workaround, put the class definitions in a separate file and edit them without opening the model that creates instances. The probable reason is that MoMLParser handles propagation by issuing large numbers of change requests.
• Certain actors, such as MathFunction, change the number of ports when parameters change. This violates the derivation invariance for classes. To demonstrate the bug, put a MathFunction actor in a base class that has a subclass. Change the function parameter in the subclass to anything but "modulo". Then change the function in the base class to "modulo" (which adds a port). Now attempt to insert a parameter into the port. You will get an InternalErrorException when it tries to propagate the change.

Limitations in the Actor Libraries

• The actor library is far from complete.
• The Expression actor does not properly propagate type constraints in an expression-dependent fashion. It works correctly for double-valued expressions of double-valued inputs.
• The Ptolemy parameter parser uses comma "," to separate elements in an array. This causes problems when Ptolemy is run on European machines that use a comma "1,0" instead of a period "1.1" in floating point numbers.
• The Display actor uses the Swing JTextArea component which is known to have memory leaks.
• The readFile() parameter function does not work with applets. Instead, use readResource().
• IterateOverArray has the following problems
  • IterateOverArray: When you drop in an actor, and then another actor, and then select "undo," the second actor is deleted without the first one being re-created. Thus, undo is only a partial undo. The fix to this is extremely complicated. Probably the only viable mechanism is to use UndoStackAttribute.getUndoInfo() to get the undo stack and then to manipulate the contents of that stack directly.
  • IterateOverArray: There should be an option to reset between firings of the inside actor.
  • IterateOverArray: If you drop a new actor onto an IterateOverArray in a subclass, it will simply acquire the new contents, but not actually do anything with them. It should somehow refuse to accept the new object in the subclass, since to do so, it would have to delete the original object defined in the base class, and this would violate the derived invariant.
  • IterateOverArray: If an instance of IterateOverArray in a derived class has overridden values of parameters, those are lost if contained entity of the instance in the base class is replaced and then an undo is requested.
  • IterateOverArray: When an actor with a display icon like Const, Expression, or MathFunction is put into IterateOverArray, the CopyCatIcon doesn't reflect the text display.

Limitations in the PN Domain

The PN domain documents that it locally handles mutations. However, this is currently not true in the implementation. For the basic PN model, this doesn't really matter, since mutations happen pretty much the same as they would otherwise. (i.e. they are non-deterministic in when they execute) However, for timed PN models, there is actually some expressiveness lost, since timed PN models can locally execute mutations deterministically.

Embedding a PN typed composite actor inside a non-process top level such as DE does not work. In fact embedding a process domain inside a non-process domain is likely to have problems. Profess Lee wrote:

Yes, it looks as if the code is designed so that process domains (PN, CSP) can only be used within process domains. I'm not sure to what extent this is a limitation of the process domains vs. a semantic problem. What would PN mean within DE? Since PN has no well-defined notion of a "firing", how would you assign time stamps to the outputs of a PN actor? By default in DE, the time stamps of the outputs of an actor match those of the inputs that triggered the firing. There is no such notion in PN.

Limitations in the User Interface

Below are some of the limitations of Vergil, the Ptolemy II Graphical User Interface.

• The labeling of ports gets messed up if you change cardinality.
• Cancelling a style change doesn't restore original state. There are FIXME's about this in actor.gui.style.StyleConfigurer.
• If there are multiple windows open for a model, say, the top level vergil window and the tree view, or the top level window and the inside look of a composite component, when the top level window is closed, all other windows are closed, but the user is not prompted to save any change to the model.
• When setting the type of a port, we should provide a combo box that lists the common ports
• When creating a Modal Model, use Control-Right-Button to drawn arcs between nodes. One potential workaround would be to have an information message in the status bar about this.
• You should not change the names of built in ports - The port mechanism should disallow port name changes on ports that are named in Java. The UI could recognize this. The UI should not allow the user to remove built in Java defined ports.
• Manually setting of the types of actors like ArrayToSequence that have constraints on their element types can cause problems.
• HTVQ demo is badly laid out when run under vergil.
• Weak support for multiports in the graph editor.
• It is difficult to control wire routing.
• Cannot have more than one vertex in a connection.
• No mechanism to set the width of a relation.
• The integrated web browser is not a full-featured browser.
• Debugger not yet integrated.
• It is difficult to add actors to the libraries.
• No dynamic class reloading.
• Plot windows don't resize when control panel is resized
  If a model with plotters is executed using the run button on the toolbar, and then re-executed using the run control panel accessed through the View menu, then resizing the run control panel does not cause the plots to resize to fit.
  Workaround: Close the model and re-open it, and then run first using the run control panel.
• There is no mechanism in the UI to save a model as a class, nor to save a submodel as a class.
• There is no mechanism in the UI to create a custom icon for a library element and store it in the right place.
• If an actor uses a slider, then the actor tree navigator pane incorrectly shows the slider as a subitem of the actor.
• It seems that if you close a model that has been modified, get prompted to save it, and select save, then the model is saved but not closed. It should be closed too...
• When I select a large number of items from one model, and copy and paste them into a new one, they sometimes all get placed at the origin. Strangely, if I then auto-place, and then undo, they get their original (correct) placement!
• Printing a model that contains transparent objects can result in problems when printing to Encapsulated Postscript (EPS).
  If a model has transparent objects, then when it is printed to EPS, the resulting file is a bitmap instead of a Postscript description of the graphics. You can tell by the file size (several Meg vs. several K) and by opening it in Illustrator, where in theory you should be able to ungroup and select and edit individual components.
  The way Java prints EPS is that there is an implementation of Graphics2D that literally translates each graphics2D call into a Postscript snippet. If Java detects any transparent colors or images, then the literal translation of each element independently doesn't work, so the printing code reverts to writing everything to an image and then sending the image, encapsulated in Postscript to the printer.
  Solution1: Use one of these pdf writing programs to generate pdf-1.4 compliant pdf files, which have extensions to support transparency that Postscript lacks, and then print them to eps, which would use the distill implementation of the above algorithm. Or alternatively, we could switch to using pdftex instead of latex->dvips->distill which should embed pdf for figures directly at the expense of less robust latex support. http://www.geocities.com/marcoschmidt.geo/java-libraries-pdf.html
  Solution 2: Use the undocumented flag -Dsun.java2d.print.pipeline=pdl on the command line to force the printing to use the postscript path, ignoring transparency. Under Cygwin:

  	  export JAVAFLAGS=-Dsun.java2d.print.pipeline=pdl
  	  vergil
  	

  Then edit the file by hand in Illustrator to add the transparency back in.

Limitations in JNI

• The Interface to C actors using the Java Native Interface is not available via the Windows Installer (or Web Start). To use the JNI/Ptolemy II interface, you must download Ptolemy II as source files and compile.
• The JNI user interface was removed between Ptolemy II 4.0 and Ptolemy II 7.0 because the UI stopped working.

Code Generation Limitations

Missing Domains

• Boolean and integer dataflow.

For limitations discovered after the release, see the Ptolemy II 10.0.1 website