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G.2 Common problems while running pigi

pxgraph fails to come up or displays a blank window

If the pxgraph program is given exceptional numbers, such as the IEEE floating-point Inf, -Inf, or NaN ("not a number"), then it will issue a cryptic error message "problems with input data" and will fail to display a plot. The stars that use pxgraph are supposed to intercept this and pop up an error message in a window. However, as of this writing, this does not work on all platforms. On such platforms, the error message, unfortunately, goes to the standard output, which may be buried several layers deep in your windowing system. It is also possible for the standard output to be lost, so that no error message appears. Thus, if you get such a pxgraph failure, look for instabilities in your Ptolemy schematic that would cause it to produce such exceptional numbers.

Old flowgraphs do not work (facets are inconsistent)

A pigi schematic contains references to icons. These icons are referenced by their location in the file system, typically using either an absolute path, a path relative to user's home directory, or a path relative to the environment variable PTOLEMY. If the master for any of these icons is not in the expected place, vem will issue a warning, telling you the facet is inconsistent, and there will be blank space in place of the icon in the schematic. To find out what icon masters are missing, run the program masters. Instructions for doing this are given in "Copying and moving designs" on page 2-60. Invalid masters will be labeled "INVALID". You must replace the invalid reference with a reference to a valid master. The tcl script $PTOLEMY/bin/ptfixtree can be useful for changing large numbers of facets. $PTOLEMY/bin/ptfixtree.tcl file contains limited instructions on how to use it.

One typical scenario for users upgrading from an earlier version of Ptolemy is that they will have references to ~ptolemy in the directory tree. But the newer version may be installed somewhere else. One solution is to use the masters program to replace references to ~ptolemy with $PTOLEMY.

Ptolemy simulations do not stop

In the SDF domain, it is possible to have multirate systems where a single iteration fires a very large number of stars. This happens when the number of samples produced or consumed by various connected stars in the system are mutually prime, or they have very large least common multiples. If a simulation is taking an unreasonable amount of time, then look for such mutually prime numbers (e.g, rates such as 53:97). Sometimes, in such circumstances, it can take a long time for the simulation to respond to pushing the "stop" button. It should, however, eventually respond.

Multi-porthole galaxies fail

If a galaxy contains a input or output multi-porthole, and the icon of the galaxy is named Foo.input=2, Foo.output=2, etc., the galaxy will fail to compile. This is because Ptolemy behaves as if anything ending in input=X or output=X must be a star. Avoid using names like Foo.input=3 for galaxies.

Star is a compiled-in star and cannot be dynamically loaded

When you create a new universe (schematic), the domain assigned to the universe by default is SDF. If you create stars in the palette that are from another domain and then try to run the universe, you may get the error message

star `Poisson' is a compiled-in star of domain DE. Cannot dynamically load a compiled-in star class. The solution is to change the domain of the universe by choosing edit-domain from the pigi menu (the keyboard short cut is `d').

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