Troubleshooting Ptplot

Other sources of information:

Below is a list of common Ptplot problems.

Problems starting ptplot or running applets

Security violation

One known problem is that if you have a CLASSPATH environment set when you started your browser, you may get an error message when accessing some of the demos. We suggest unsetting this environment variable, restarting your browser (and sending email to Sun's Java team to complain about the way the CLASSPATH environment variable works). You may also want to check the Java FAQ.

If you have CLASSPATH set, and you run Netscape, then you might see messages like:

Applet Marks can't start: security violation: security.class
from local disk trying to access url:
http://ptolemy.eecs.berkeley.edu/java/ptolemy/plot/demo/data.plt

The CLASSPATH variable is by far and above the trickiest thing to get right.

Script fails with: Exception in thread "main" java.lang.NoClassDefFoundError: ptolemy/plot/plotml/EditablePlotMLApplication

Here is an example

bash-2.02$ ./ptplot
./ptplot: Could not find '/tmp/ptolemy/plot'.  Perhaps your PTII
 variable is not set properly?
Exception in thread "main" java.lang.NoClassDefFoundError: ptolemy/plot/plotml/EditablePlotMLApplication

The problem here is that the pxgraph script cannot find the ptplot installation. This probably means that your PTII environment variable is not set correctly. Set it to point to the home directory of the plot or Ptolemy II distribution.

To debug such a situation completely, use which (on Unix) or type (on Windows with Cygwin) to find out which ptplot script is running, and the run it with the sh -x flag: First we run which:

bash-2.02$ type ptplot
ptplot is /users/cxh/ptII/bin/ptplot

The we use sh -x. Note that the output you see might be different, depending on what version of the pxgraph script you are running.

bash-2.02$ sh -x /users/cxh/ptII/bin/ptplot
+ PTII_DEFAULT=/users/cxh/ptII_old
+ PTJAVA_DIR=/jdk1.2.2
+ '[' -z '' ']'
+ '[' -d /users/cxh/ptII_old ']'
+ PTII=/users/cxh/ptII_old
+ export PTII
+ '[' '!' -d /users/cxh/ptII_old/ptolemy/plot ']'
+ echo '/users/cxh/ptII/bin/ptplot: Could not find '\''/users/cxh/ptII_old/ptole
my/plot'\''.  Perhaps your PTII'
/users/cxh/ptII/bin/ptplot: Could not find '/users/cxh/ptII_old/ptolemy/plot'.
Perhaps your PTII
+ echo ' variable is not set properly?'
 variable is not set properly?
++ basename /users/cxh/ptII/bin/ptplot
+ '[' ptplot = pxgraph ']'
++ basename /users/cxh/ptII/bin/ptplot
+ '[' ptplot = histogram ']'
+ javastartupclass=ptolemy.plot.plotml.EditablePlotMLApplication
+ windows=no
+ windows=yes
+ '[' -z '' ']'
+ '[' -d /jdk1.2.2 ']'
+ JAVAHOME=/jdk1.2.2
+ export JAVAHOME
+ '[' -z /jdk1.2.2 ']'
+ '[' -z /jdk1.2.2 ']'
+ '[' yes = yes ']'
++ cd /users/cxh/ptII_old
++ cmd /c chdir
++ tr -d '\r'
+ WINPTII=D:\users\cxh\ptII_old
+ /jdk1.2.2/bin/java -classpath 'D:\users\cxh\ptII_old;/jdk1.2.2\lib\classes.zip' ptolemy.plot.plotml.EditablePlotMLApplication
Exception in thread "main" java.lang.NoClassDefFoundError: ptolemy/plot/plotml/E
ditablePlotMLApplication
bash-2.02$

In the output below, the key line is the line towards that bottom that runs the java interpreter:

+ /jdk1.2.2/bin/java -classpath 'D:\users\cxh\ptII_old;/jdk1.2.2\lib\classes.zip' ptolemy.plot.plotml.EditablePlotMLApplication

In the ptplot script, the first element in the -classpath argument should be a pathname that leads to the top of the Ptolemy II or Ptplot directory tree.

In this case, there are two problems, one is that $PTII is not set, so the script is using the value of PTII_DEFAULT which was hardwired into the script when configure was run. Unfortunately, the ptplot script was left over from an old installation, and at the top of the script PTII_DEFAULT was set to /users/cxh/ptII_old is an empty directory that does not contain a Ptolemy II tree.

The fix is to rerun configure and make install so that the ptplot script is properly set up.

Another common fix is to edit the pxgraph script and change the variables at the top to point to the proper location.

Last Updated: $Date: 1999/08/20 01:22:43 $