[SOLVED] Different results for Generalized Hebbian (GHA) in loop

MaggiD

In my opinion the following problem constitutes a bug, but maybe I'm doing something wrong.

I am using the Generalized Hebbian Algorithm (GHA) Operator and everything works fine until I use it inside a "Loop parameters" Operator. I use the loop so that I can run the GHA Operator with different parameters for the number of components. However if the loop does multiple iterations I get different results compared to a single execution.
My investigation of the problem showed that beginning with the 2nd loop iteration the GHA operator is calculating a different premodel. There seems to be a side effect from the previous iteration.

My process:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="6.0.006">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="6.0.006" expanded="true" name="Process">
    <process expanded="true">
      <operator activated="true" class="loop_parameters" compatibility="6.0.006" expanded="true" height="76" name="Loop Parameters" width="90" x="179" y="165">
        <list key="parameters">
          <parameter key="GHA.number_of_components" value="[3;4;2;linear]"/>
        </list>
        <process expanded="true">
          <operator activated="true" class="retrieve" compatibility="6.0.006" expanded="true" height="60" name="Retrieve w1024_training" width="90" x="45" y="75">
            <parameter key="repository_entry" value="//Anwendungsfall/w1024_training"/>
          </operator>
          <operator activated="true" class="generalized_hebbian_algorithm" compatibility="6.0.006" expanded="true" height="94" name="GHA" width="90" x="246" y="75">
            <parameter key="number_of_components" value="4"/>
          </operator>
          <operator activated="true" class="support_vector_machine" compatibility="6.0.006" expanded="true" height="112" name="SVM" width="90" x="380" y="75"/>
          <operator activated="true" class="retrieve" compatibility="6.0.006" expanded="true" height="60" name="Retrieve w1024_test_set" width="90" x="45" y="255">
            <parameter key="repository_entry" value="//Anwendungsfall/w1024_test_set"/>
          </operator>
          <operator activated="true" class="apply_model" compatibility="6.0.006" expanded="true" height="76" name="Apply Model" width="90" x="246" y="255">
            <list key="application_parameters"/>
          </operator>
          <operator activated="true" class="apply_model" compatibility="6.0.006" expanded="true" height="76" name="Apply Model (2)" width="90" x="380" y="255">
            <list key="application_parameters"/>
          </operator>
          <operator activated="true" class="performance_classification" compatibility="6.0.006" expanded="true" height="76" name="Performance" width="90" x="514" y="165">
            <list key="class_weights"/>
          </operator>
          <connect from_op="Retrieve w1024_training" from_port="output" to_op="GHA" to_port="example set input"/>
          <connect from_op="GHA" from_port="example set output" to_op="SVM" to_port="training set"/>
          <connect from_op="GHA" from_port="preprocessing model" to_op="Apply Model" to_port="model"/>
          <connect from_op="SVM" from_port="model" to_op="Apply Model (2)" to_port="model"/>
          <connect from_op="Retrieve w1024_test_set" from_port="output" to_op="Apply Model" to_port="unlabelled data"/>
          <connect from_op="Apply Model" from_port="labelled data" to_op="Apply Model (2)" to_port="unlabelled data"/>
          <connect from_op="Apply Model (2)" from_port="labelled data" to_op="Performance" to_port="labelled data"/>
          <connect from_op="Performance" from_port="performance" to_port="result 1"/>
          <portSpacing port="source_input 1" spacing="0"/>
          <portSpacing port="sink_performance" spacing="0"/>
          <portSpacing port="sink_result 1" spacing="0"/>
          <portSpacing port="sink_result 2" spacing="0"/>
        </process>
      </operator>
      <operator activated="true" class="collect" compatibility="6.0.006" expanded="true" height="76" name="Collect" width="90" x="380" y="165"/>
      <connect from_op="Loop Parameters" from_port="result 1" to_op="Collect" to_port="input 1"/>
      <connect from_op="Collect" from_port="collection" to_port="result 1"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="0"/>
      <portSpacing port="sink_result 2" spacing="0"/>
    </process>
  </operator>
</process>
[ /code]

homburg

Hi MaggiD,

thanks for sending your process file. The problem you described will very likely occur due to a non-fixed random seed value. I'd recommend to check "use local random seed" option. Please note that you might have to enable the expert mode to see this option.

Cheers,
Helge

MaggiD

Thank you very much, I didn't know about random seed before