marvin_souzamarvin_souza Member Posts: 2 Contributor I
edited November 2018 in Help
Hi all.
I am using the RapidMiner to do Task Inference in my Master tesis. After some tests with different data, occured a strange error.
First I will describe my scenario.
<operator name="Root" class="Process" expanded="yes">
    <operator name="DatabaseExampleSource" class="DatabaseExampleSource">
        <parameter key="database_system" value="PostgreSQL"/>
        <parameter key="database_url" value="jdbc:postgresql://parara:5432/exehda"/>
        <parameter key="username" value="marcos"/>
        <parameter key="password" value="vBwyakUxtRE="/>
        <parameter key="query" value="SELECT as task,h.sector, h.time_frame, h.main_device,, sec.type  FROM  exehda_history h left join exehda_history_sec_ctx sec on  join exehda_task t on h.id_task = where h.id_user = 1"/>
        <parameter key="label_attribute" value="task"/>
        <parameter key="datamanagement" value="double_sparse_array"/>
    <operator name="DecisionTree" class="DecisionTree">
        <parameter key="criterion" value="information_gain"/>
        <parameter key="minimal_size_for_split" value="5"/>
        <parameter key="minimal_leaf_size" value="3"/>
        <parameter key="minimal_gain" value="0.2"/>
        <parameter key="number_of_prepruning_alternatives" value="2"/>
        <parameter key="no_pre_pruning" value="true"/>
        <parameter key="no_pruning" value="true"/>
My data:

AtendimentoPaciente clinica 43 desktop (null) (null)
AtendimentoPaciente clinica 42 desktop (null) (null)
AtendimentoPaciente clinica 42 desktop (null) (null)
AtendimentoPaciente clinica 41 desktop (null) (null)
AtendimentoPaciente clinica 41 desktop (null) (null)
AtendimentoPaciente clinica 40 desktop (null) (null)
AtendimentoPaciente clinica 40 desktop (null) (null)
Cirurgia         clinica 45 desktop (null) (null)
When I run this proccess, I got the error:

java.lang.ArrayIndexOutOfBoundsException: 0
    at com.rapidminer.operator.learner.tree.InfoGainCriterion.getBenefit(
    at com.rapidminer.operator.learner.tree.InfoGainCriterion.getNominalBenefit(
    at com.rapidminer.operator.learner.tree.TreeBuilder.calculateBenefit(
    at com.rapidminer.operator.learner.tree.TreeBuilder.calculateAllBenefits(
    at com.rapidminer.operator.learner.tree.TreeBuilder.buildTree(
    at com.rapidminer.operator.learner.tree.TreeBuilder.learnTree(
    at com.rapidminer.operator.learner.tree.AbstractTreeLearner.learn(
    at com.rapidminer.operator.learner.AbstractLearner.apply(
    at com.rapidminer.operator.Operator.apply(
    at com.rapidminer.operator.OperatorChain.apply(
    at com.rapidminer.operator.Operator.apply(
If the data is generated randomically, this don't happen. Some suggestion ?


  • marvin_souzamarvin_souza Member Posts: 2 Contributor I
    By some obscure reason, the RM don't handles the null values.
    When I remove the columns info and type, everything works fine.
  • steffensteffen Member Posts: 347 Maven
    Hello marvin

    I assume that the data is loaded as "(null)", not as missing values. Correct ?
    Another Question: Do the mentioned columns have each only one unique value ?


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