[SOLVED] Does "Set Data" operator propagate results backward?

tennenrishin

After running the following process, why is the value of x in /dbg2/b equal to 123 and not 0?

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.3.005">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="5.3.005" expanded="true" name="Process">
    <process expanded="true">
      <operator activated="true" class="generate_data_user_specification" compatibility="5.3.005" expanded="true" height="60" name="Generate Data by User Specification" width="90" x="179" y="120">
        <list key="attribute_values">
          <parameter key="a" value="&quot;&quot;"/>
          <parameter key="b" value="&quot;&quot;"/>
          <parameter key="x" value="0"/>
        </list>
        <list key="set_additional_roles"/>
      </operator>
      <operator activated="true" class="loop_attributes" compatibility="5.3.005" expanded="true" height="76" name="bubble plots" width="90" x="313" y="120">
        <parameter key="attribute_filter_type" value="regular_expression"/>
        <parameter key="regular_expression" value="[ab]"/>
        <process expanded="true">
          <operator activated="true" class="filter_examples" compatibility="5.3.005" expanded="true" height="76" name="not missing" width="90" x="45" y="30">
            <parameter key="condition_class" value="attribute_value_filter"/>
            <parameter key="parameter_string" value="%{loop_attribute}!=\?"/>
          </operator>
          <operator activated="true" class="store" compatibility="5.3.005" expanded="true" height="60" name="Store (4)" width="90" x="179" y="120">
            <parameter key="repository_entry" value="/dbg2/%{loop_attribute}"/>
          </operator>
          <operator activated="true" class="set_data" compatibility="5.3.005" expanded="true" height="76" name="set x 123" width="90" x="313" y="120">
            <parameter key="example_index" value="1"/>
            <parameter key="attribute_name" value="x"/>
            <parameter key="value" value="123"/>
            <list key="additional_values"/>
          </operator>
          <connect from_port="example set" to_op="not missing" to_port="example set input"/>
          <connect from_op="not missing" from_port="example set output" to_op="Store (4)" to_port="input"/>
          <connect from_op="not missing" from_port="original" to_port="example set"/>
          <connect from_op="Store (4)" from_port="through" to_op="set x 123" to_port="example set input"/>
          <portSpacing port="source_example set" spacing="0"/>
          <portSpacing port="sink_example set" spacing="0"/>
          <portSpacing port="sink_result 1" spacing="0"/>
        </process>
      </operator>
      <connect from_op="Generate Data by User Specification" from_port="output" to_op="bubble plots" to_port="example set"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="0"/>
    </process>
  </operator>
</process>

Regards,
Isak

Marco_Boeck

Hi,

RapidMiner works with views on the data for most operators (so the underlying data is not changed), however some operators do modify the underlying data directly and this is one of them. To avoid such a problem in a loop, you can use the "Materliaze Data" operator before you store the data, this will create a clean & fresh copy of the data.

Regards,
Marco

tennenrishin

Thanks Marco. I was relieved to find that workaround.

I suppose this is for performance. Maybe it would be a good idea to add a "Create View" parameter such as that of the "Replace Missing Values" operator. IMhO the default (for both operators) should be true. Otherwise they don't uphold the graphical model of RM processes.

Regards,
Isak