[kepler-users] Type resolving problem

[Christopher Brooks]

Hi Tomasz,
I created a test case that fails (attached).

The problem is that if I use the Expression actor with concatenate(),
then the output is arrayType(general) instead of arrayType(string,3).

You wrote:

> Hi,
>
> I've read the documentation about expressions, because what I need is to concatenate two arrays of type: string. When I run it inside Expression Evaluator I get:
>
>>> t1 = {"a"}
> {"a"}
>>> t2 = {"b"}
> {"b"}
>>> t1.getType()
> object(arrayType(string,1))
>>> t2.getType()
> object(arrayType(string,1))
>>> concatenate(t1, t2)
> {"a", "b"}
>>> concatenate(t1, t2).getType()
> object(arrayType(string,2))
>
> This is correct and such behaviour is what I'd like to have. However in Kepler, expression actor always returns type "general" after concatenation no matter what are its input types. Because of this, I cannot run my workflow as I get type resolve exception.
>
> I tried configuring output port of expression actor with no effect. I tried also to use cast() function, with no effect either. Last thing, I cannot use Concatenate Arrays actor, because the number of arrays is not known during workflow design - it is determined during runtime, so I must do it in a loop.
>
> Do you have any ideas what may cause the problem?

I think the problem may be with ptolemy.data.expr.UtilityFunctions.
The concatenate expression language function is defined as:

   /** Concatenate two arrays.
      *  The arrays must have the same type.
      *  Example: concatenate({1,2,3},{4,5,6}) == {1,2,3,4,5,6}.
      *  @param token1 First array from which tokens are copied to the result.
      *  @param token2 Second array from which tokens are copied to the result.
      *  @return An array containing all of the elements of the first argument
      *   (in order), followed by all of the arguments of the second argument
      *   (in order).
      *  @exception IllegalActionException If the arrays do not have
      *   compatible types.
      *  @since Ptolemy II 4.1
      */
     public static ArrayToken concatenate(ArrayToken token1, ArrayToken token2)
             throws IllegalActionException {
         Token[] array1 = token1.arrayValue();
         Token[] array2 = token2.arrayValue();

         int nElements = array1.length + array2.length;
         Token[] resultArray = new Token[nElements];

         System.arraycopy(array1, 0, resultArray, 0, array1.length);
         System.arraycopy(array2, 0, resultArray, array1.length, array2.length);

         return new ArrayToken(resultArray);
     }

     /** Concatenate an array of arrays into a single array.
      *  Example: concatenate({{1,2,3},{4,5},{6,7}}) == {1,2,3,4,5,6,7}.
      *  @param token Array of arrays which are to be concatenated.
      *  @exception IllegalActionException If the argument is not an array of
      *   arrays.
      *  @since Ptolemy II 4.1
      */
     public static ArrayToken concatenate(ArrayToken token)
             throws IllegalActionException {
         if (!(token.getElementType() instanceof ArrayType)) {
             throw new IllegalActionException(
                     "The argument to concatenate(ArrayToken) "
                             + "must be an array of arrays.");
         }

         int nElements = 0;

         for (int i = 0; i < token.length(); i++) {
             nElements += ((ArrayToken) (token.getElement(i))).length();
         }

         Token[] result = new Token[nElements];
         int cursor = 0;

         for (int i = 0; i < token.length(); i++) {
             Token[] array = ((ArrayToken) (token.getElement(i))).arrayValue();
             System.arraycopy(array, 0, result, cursor, array.length);
             cursor += array.length;
         }

         return new ArrayToken(result);
     }

I wonder if we need to be more explicit about setting the size of the array?

I'm on vacation until September 7 or 8, so someone else would need to take
a look.

_Christopher




On 8/26/10 11:50 PM, Tomasz Żok wrote:
> Christopher Brooks <cxh at eecs.berkeley.edu>:
>> Do you have a small test case?
>
> In the attachment you can find two files:
> - model.xml is a workflow
> - scr1.png is a screenshot from workflow execution
>
> The screenshot shows also the tooltip displayed on output port of
> expression actor. There is "arrayType(general)", but according to input
> array types and an excerpt from expression evaluator, it should be
> "arrayType(string)".
>
> However I found out today that it can work with cast() function:
> cast(arrayType(string), concatenate(t1, t2))
>
> Yesterday I wrote, that cast() did not help, but I made a mistake. Sorry
> for misleading you with this.
>
>
> But still - is this behaviour without cast() correct and expected?
>
> Best regards,
> Tomek
>

-- 
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 fax:510.642.2718	      (Office: 545Q Cory)
home: (F-Tu) 707.665.0131 cell: 707.332.0670
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