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Incorrect or $null values generated when using Filler node in PASW Modeler 14.0.1 and error messages in Modeler 14.0.2

Technote (troubleshooting)


In PASW Modeler 14.0.0 or 14.0.1, when you execute a task by using OFFSET function in a Filler node, you get different results in Modeler 13 and Modeler 14. When using the @OFFSET function, it is not retrieving the correct data value when used in conjunction with an IF statement.

For example:
In Modeler 13, if I want Modeler to retrieve a value of a future case if a cell was empty, I would use the following inside a 'FILLER' node:

if <variable1> = undef and @OFFSET('<variable2>',-1)='<variable2>' then @OFFSET(<variable1>,-1)
else <variable1>

I would get valid results to fill in the undefined variables. However in Modeler 14.0.0 or 14.0.1, using the same settings in the FILLER node will still return '$null' values.

Resolving the problem

This has been reported to development and due to more serious defects, this feature has been dropped from the FILLER node in Modeler 14.0.2 onwards.

Due to a number of issues regarding the @OFFSET function in Modeler, where customers were being shown incorrect data, IBM SPSS has decided to make a range of fixes that relate to the function of self-referential fillers where the old (pre-filled) values were being referenced instead of the updated values as expected. For more information on these issues, please see the following resolution ID's: 90424; 87237; 88833

IBM SPSS has decided that rather than allow our program to display incorrect data, you will be warned with an error message.

If you use the @OFFSET function, which looks ahead of the data and return back with a value, the error you'll receive reads:

"Self-referential @OFFSET function cannot use literal look-ahead"

If you use the '@LAST_NON_BLANK' function, the message reads:

"Internal Error: Impossible case in file "code_generator.cpp"

A simple workaround of using a DERIVE node instead of a FILLER node will provide the data you require.
E.g. Instead of using a FILLER node containing:
@BLANK(@FIELD) and @OFFSET(<var>,1)=id
Replace with:

Use the following in a DERIVE node with:
@BLANK(@FIELD) and @OFFSET(<var>,1)=id

And then use a FILTER node to remove the original fields and replace them with the newly generated ones.

IBM SPSS would like to sincerely apologise for the confusion and inconvenience this has caused

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Document information

More support for: SPSS Modeler

Software version: 14.1, 14.2, 15.0

Operating system(s): Windows

Reference #: 1487662

Modified date: 07 September 2016

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