[kepler-users] Kepler: Array instantiation and Array element assignment

Mon Oct 1 22:01:01 PDT 2012

Hi Christopher,

Thanks for the email.  Now the fact that that we can interface with C /C++ is good news.  At the moment I am evaluating a possible framework for us to use with our project related to climate model analysis.  I have used Kepler to create actors related to climate studies using the composite actor and they are working well.  I am heartened by fact that the user group has been very responsive and helpful as I learn this framework.

I ended using what you suggested, that is using a Parameter actor that can be seen workflow wide.  Am I allowed to say  "the variable is local to the workflow actor"  :).

Thanks again,

Ric

From: Christopher Brooks [mailto:cxh at eecs.berkeley.edu]
Sent: Tuesday, 2 October 2012 12:00 PM
To: Pascual, Ricardo (CMAR, Dutton Park)
Cc: barseghian at nceas.ucsb.edu; Kepler-users at kepler-project.org
Subject: Re: [kepler-users] Kepler: Array instantiation and Array element assignment

Hi Ricardo,

Interfacing to C is not that difficult, though it is difficult to do in a portable manner.
See
http://docs.oracle.com/javase/7/docs/technotes/guides/jni/

I used JNA (https://github.com/twall/jna) with good success to interface to FMI, see org/ptolemy/fmu.

The JNAerator will create stub code for you from C and C++
http://code.google.com/p/jnaerator/

Ptolemy II includes ways to access C code, see the faq links below.
See $PTII/bin/vergil $PTII/ptolemy/cg/lib/demo/Scale/ScaleC.xml

For interfacing to a C library that is complex, I suggest using JNA to create some wrapper Java code and then write actors that use the Java wrapper code.

I don't really understand your initial question though.  What are you trying to do?

You said you wanted to create a "scope workflow wide".  Typically, we do this by placing a parameter into a model.

If you were writing Java code, you would create a parameter in the container of an actor, but this is not very good actor-oriented programming.

For information about writing actors in Java,  see the designing actors chapter of http://www.eecs.berkeley.edu/Pubs/TechRpts/2008/EECS-2008-28.html

_Christopher

On 10/1/12 6:04 PM, Ricardo.Pascual at csiro.au<mailto:Ricardo.Pascual at csiro.au> wrote:
Hi Derik,

Thanks for the email.   Somehow I need to interface with C/C++ codes as there are codes that I will need written in C/C++.

It is good to know that there is an active forum on Kepler.

Cheers,

Ric

From: Derik Barseghian [mailto:barseghian at nceas.ucsb.edu]
Sent: Tuesday, 2 October 2012 10:56 AM
To: Pascual, Ricardo (CMAR, Dutton Park)
Cc: kepler-users at kepler-project.org<mailto:kepler-users at kepler-project.org> Users
Subject: Re: [kepler-users] Kepler: Array instatiation and Array element assignment

Hi Ric,

I found some relevant info here;
http://ptolemy.eecs.berkeley.edu/ptolemyII/ptIIfaq.htm#Interfacing to C/C++<http://ptolemy.eecs.berkeley.edu/ptolemyII/ptIIfaq.htm#Interfacing%20to%20C/C++>
http://ptolemy.eecs.berkeley.edu/ptolemyII/ptIIfaq.htm#CodeGen
The descriptions make it sound like these aren't being worked on anymore, but I've seen ptolemy SVN check-ins that seem to do w/ C code generation and copernicus in the recent past, so I'm not sure about that.

Note you can call any arbitrary program using the External Execution actor.

If you're trying to develop new actor(s), customizing the RExpression or Python actors, or writing new ones in Java is probably easiest.
Derik

On Oct 1, 2012, at 8:46 AM, "Edward A. Lee" <eal at eecs.berkeley.edu<mailto:eal at eecs.berkeley.edu>> wrote:

The SetVariable actor is rather tricky to use.
Depending on the director that you choose and the parameters you set,
it could be nondeterministic.  Why go through a variable? Why not just
feed the data from DirectoryListing to where it is needed?

If there are lots of places it is needed, you might consider using
Publisher and Subscriber.  These, at least, are assured of determinism.

It is a bit of a change of mindset to "think in kepler" :-)
It's quite important which director you pick. They all provide
a concurrent model of computation, but their behaviors are quite
different...

Edward

On 9/30/12 8:49 PM, Ricardo.Pascual at csiro.au<mailto:Ricardo.Pascual at csiro.au> wrote:

Hi Edward.

Thanks for the email.  I am still trying to to learn how to think properly in kepler.  Any how the best solution  I can come up with is defining a parameter actor and setting the value using the VariableSetter actor. I believe you created this actor.  So if I set it to an array of strings dirList will be an array of string as in below.
*dirList  #"declare the variable as ParameterActor"
DirectoryListingActor -----> VariableSetterActor(with .variablename =dirList)

There might be a more elegant solution but that will have to wait until I know more of kepler.  As you pointed out you can do this with the various Expression like RExpression and others. BTW is there a hook to C++ in kepler?

Kind regards.

Ric
________________________________________
From: Edward A. Lee [eal at eecs.berkeley.edu<mailto:eal at eecs.berkeley.edu>]
Sent: Monday, 1 October 2012 7:02 AM
To: Pascual, Ricardo (CMAR, Dutton Park)
Cc: Kepler-users at kepler-project.org<mailto:Kepler-users at kepler-project.org>; cxh at eecs.berkeley.edu<mailto:cxh at eecs.berkeley.edu>; crawl at sdsc.edu<mailto:crawl at sdsc.edu>
Subject: Re: [kepler-users] Kepler: Array instatiation and Array element assignment

Hi Ric,

I'm not sure what you mean by "programmatically."
What you describe below is a program in an imperative language.
In Kepler, the primary imperative language is Java. So you
could write an actor in Java that does this.

There are also hooks to write actors in MATLAB and Python,
which are also imperative languages.

If instead you are trying to define a workflow that builds
this variable, then the only director with an imperative
flavor is the FSM. I think it could be awkward to define
it in an FSM.

You could use a dataflow director or PN and SequenceToArray
actor, but these are distinctly not imperative.

In Kepler, parameters are defined as expressions in the
Ptolemy expression language.
The expression language is also not an imperative language.
It is a functional language. So you don't actually specify
sequences of steps for defining variables.

It occurs to me that it could be very useful to define
subclass of Parameter, say PythonParameter, that specifies
a parameter value that is initialized by running a Python
script... This would probably be fairly easy to write...
Any interest in this?

Edward

On 9/30/12 12:39 PM, Ricardo.Pascual at csiro.au<mailto:Ricardo.Pascual at csiro.au> wrote:

Hi All,

Oooops wrong title.

Thanks,

Ric

________________________________________
From: kepler-users-bounces at kepler-project.org<mailto:kepler-users-bounces at kepler-project.org> [kepler-users-bounces at kepler-project.org<mailto:kepler-users-bounces at kepler-project.org>] On Behalf Of Ricardo.Pascual at csiro.au<mailto:Ricardo.Pascual at csiro.au> [Ricardo.Pascual at csiro.au<mailto:Ricardo.Pascual at csiro.au>]
Sent: Sunday, 30 September 2012 9:11 PM
To: Kepler-users at kepler-project.org<mailto:Kepler-users at kepler-project.org>; cxh at eecs.berkeley.edu<mailto:cxh at eecs.berkeley.edu>; crawl at sdsc.edu<mailto:crawl at sdsc.edu>
Subject: [ExternalEmail] Re: [kepler-users] netCDF

Hi All,

I am about a week old into Kepler and having difficulty defining an array variable programmatically.  I have search the internet for this to no avail.   I know how to do it as a constant by assigning the value = {"x1", ...}.

What I like to do is define a variable with scope workflow wide say

string fileNames[];

then assign values to it as in

fileNames[0] = "file0"
fileNames[1] = "file1"

and so on.

Thank you very much,

Ric
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--

Christopher Brooks, PMP                       University of California

CHESS Executive Director                      US Mail: 337 Cory Hall

Programmer/Analyst CHESS/Ptolemy/Trust        Berkeley, CA 94720-1774

ph: 510.643.9841                                (Office: 545Q Cory)

home: (F-Tu) 707.665.0131 cell: 707.332.0670
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