Nullpointer in Lib SVM Learner

KNIME Analytics Platform
1

Hi everyone,

I am currently getting a Nullpointer Exception after running a LIBSVMLearner Node (Weka 3.7, epsilon-SVR) repeatedly in a parameter optimization loop.
It works fine for many iterations, and then suddenly stops.

The log file reads:

DEBUG : KNIME-Worker-15 : LocalNodeExecutionJob : LIBSVMLearner : 0:110 : Caught "NullPointerException": null
java.lang.NullPointerException
    at libsvm.svm.svm_get_svm_type(svm.java:2238)
    at org.knime.ext.libsvm.port.LIBSVMPortObject.getSummary(LIBSVMPortObject.java:196)
    at org.knime.core.node.Node.setOutPortObjects(Node.java:1242)
    at org.knime.core.node.Node.execute(Node.java:1017)
    at org.knime.core.node.workflow.NativeNodeContainer.performExecuteNode(NativeNodeContainer.java:561)
    at org.knime.core.node.exec.LocalNodeExecutionJob.mainExecute(LocalNodeExecutionJob.java:95)
    at org.knime.core.node.workflow.NodeExecutionJob.internalRun(NodeExecutionJob.java:179)
    at org.knime.core.node.workflow.NodeExecutionJob.run(NodeExecutionJob.java:110)
    at org.knime.core.util.ThreadUtils$RunnableWithContextImpl.runWithContext(ThreadUtils.java:328)
    at org.knime.core.util.ThreadUtils$RunnableWithContext.run(ThreadUtils.java:204)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at org.knime.core.util.ThreadPool$MyFuture.run(ThreadPool.java:123)
    at org.knime.core.util.ThreadPool$Worker.run(ThreadPool.java:246)

Any idea what I could do?
I have tried setting the Learner Type via a Flow Variable, that didn't help.
I have also checked the optimization parameters(gamma and epsilon), they are both somewhere in the middle of their range and not zero.

KNIME Version is 3.4.0.

Kindest regards,
Mol1hua

2

Hi Mol1hua,

can you provide your workflow so we can reproduce the issue?

Cheers,
Marten

3

Hi Marten,

Thank you for your reply!

I had to move the workflow to another computer, and the issue seems to have resolved itself somehow. Maybe it was a workspace hiccup?

Anyway, it seems I cannot reproduce it myself. ;-)

Kindest regards,


Mol1hua