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.pasc...@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 [e...@eecs.berkeley.edu]
Sent: Monday, 1 October 2012 7:02 AM
To: Pascual, Ricardo (CMAR, Dutton Park)
Cc: Kepler-users@kepler-project.org; c...@eecs.berkeley.edu; cr...@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.pasc...@csiro.au wrote:
Hi All,

Oooops wrong title.

Thanks,

Ric

________________________________________
From: kepler-users-boun...@kepler-project.org 
[kepler-users-boun...@kepler-project.org] On Behalf Of ricardo.pasc...@csiro.au 
[ricardo.pasc...@csiro.au]
Sent: Sunday, 30 September 2012 9:11 PM
To: Kepler-users@kepler-project.org; c...@eecs.berkeley.edu; cr...@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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