I am trying the

Ioannis

I am trying the "Extract topics from Data (LDA)" operator and i get the error listed below. 
Data input = An excel file with one column with several cells as texts.
Read Excel > Process Documents from Data > Extract topics from Data (LDA)
text attribute: I put the name of the column as attribute "text".
I tried several number of topics and iterations but the warning message is the same.
I think that sth happens with the Attribute selection.
OR
the "Process Documents from Data" produces wrong data types for the LDA.

Message says:

• Exception: java.lang.NullPointerException
• Message: null
• Stack trace:
• com.rapidminer.example.Example.getNominalValue(Example.java:97)
• com.rapidminer.extension.operator.text_processing.modelling.mallet.MalletHelper.convertToInstanceList(MalletHelper.java:60)
• com.rapidminer.extension.operator.text_processing.modelling.mallet.LDA_ExampleSet.getInstances(LDA_ExampleSet.java:69)
• com.rapidminer.extension.operator.text_processing.modelling.mallet.LDA.doWork(LDA.java:125)
• com.rapidminer.operator.Operator.execute(Operator.java:1022)
• com.rapidminer.operator.execution.SimpleUnitExecutor.execute(SimpleUnitExecutor.java:77)
• com.rapidminer.operator.ExecutionUnit$2.run(ExecutionUnit.java:812)
• com.rapidminer.operator.ExecutionUnit$2.run(ExecutionUnit.java:807)
• java.security.AccessController.doPrivileged(Native Method)
• com.rapidminer.operator.ExecutionUnit.execute(ExecutionUnit.java:807)
• com.rapidminer.operator.OperatorChain.doWork(OperatorChain.java:423)
• com.rapidminer.operator.Operator.execute(Operator.java:1022)
• com.rapidminer.Process.executeRoot(Process.java:1464)
• com.rapidminer.Process.lambda$executeRootInPool$5(Process.java:1443)
• com.rapidminer.studio.concurrency.internal.AbstractConcurrencyContext$AdaptedCallable.exec(AbstractConcurrencyContext.java:362)
• java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
• java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
• java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
• java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)

Thank you in advance for your help!

Ioannis

I think I found the solution. I would like to delete this Question @sgenzer  
Thank you! 

MartinLiebig

Hi @Ioannis ,

this is a bug which should be 'fixed' this week. You will get a proper error message in the future.

Best,

Martin