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TrainExtractor Tutorial

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linfrank edited this page Aug 16, 2012 · 1 revision

TrainExtractor Tutorial

Extraction means extracting types within documents (such as names or places). TrainExtractor tasks take text data as input. For this example we will use sample1.train as the training data. This sample is built into the code, so it requires no additional setup. To see how to label and load your own data for this task, look at the Labeling and Loading Data Tutorial.

This experiment will train on a training set and output an extractor, which can be used to test another dataset or applied to an unlabeled dataset to add labels (such as extracted_name).

Using the GUI

  1. To run this type of task using the GUI type:
$ java –Xmx500M edu.cmu.minorthird.ui.TrainExtractor –gui

  1. A window will appear. To view and change the parameters of the experiment press the Edit button located next to TrainExtractor. A Property Editor dialog box will appear:

  2. To view what each parameter does and/or how to set it, click the ? button next to each field. The parameters that must be entered for the experiment to run are baseParameters (e.g., -labels) and signalParameters (e.g., -spanType or –spanProp). All other parameters have defaults or are not required. There are 4 bunches of parameters that can be modified when running a TrainExtractor experiment:

  • Options for how MinorThird learns from the training data are in additionalParameters. These options all have defaults, so do not need to be explicitly stated. Most importantly the learner can be changed by selected a learner from the pull down menu and edited by pressing the Edit button next to learner. To view the Javadoc documentation for the currently selected learner, press the '?' button for a link to the Javadoc. The output parameter specifies how MinorThird labels extracted types. By default it is set to prediction, but it is useful to change this to something more informative such as predicted_trueName.

  • First training data for the experiment must be entered by specifying a labelsFilename. Since the samples are built into the code, sample1.train can simply be typed into the text field under labelsFilename to load the data. Note: data from a directory can be loaded by using the Browse button.

  • To save the results from the experiment, enter a file to which to write the results in the saveAs text field. Note: this is optional, yet necessary in order to use the saved extractor in the future.

  • Once labelsFilename is specified, click the Edit button next to signalParamters. Important: labelsFilename must be specified BEFORE clicking Edit. Another Property Editor will appear. Select trueName from the pull down menu. Then press the OK button to close the Property Editor for signalParameters.

  1. Feel free to try changing any of the other parameters including the ones in advanced options. Click the help buttons to get a feeling for what each parameter does and how changing it may affect your results. Once all the parameters are set, click the OK button on the Property Editor window.
  2. Press the Show Labels button if you would like to view the input data for the extraction task. This will pop up the same TextBaseViewer that you would see if you ran ViewLabels on the train data.
  3. Now press Start Task under execution controls. The task will vary in the amount of time it takes depending on the size of the data set and what learner was chosen, but extraction tasks usually take a minute or two. When the task is finished, the error rates will appear in the output text area along with the total time it took to run the experiment.
  4. When the experiment has finished running, click the View Results button to view extractor results. The features in the extractor may be sorted by name, weight (seen on the left), or absolute weight or be viewed in a tree (as seen on the right) where the root contains the highest value of the leaves below. Features with the largest weights are most highly correlated with have the specified SpanType. In this case tokens with charTypePattern capital letter followed by lower case letter is most highly correlated with trueName since it is the feature with the largest weight in the extractor.
  5. Press the Clear Window button to clear all output from the output and error messages window. This is useful if you would like to run another experiment.

Using the Command Line

  1. To get started using the command line for an extractor experiment type:
$ java –Xmx500M edu.cmu.minorthird.ui.TrainExtractor –help

Note: You can enter as many command line arguments as you like along with the –gui argument. This way you can use the command line to specify the parameters that you would like and use and use the GUI to set any additional parameters or view the results. 2. Show options - specifying these options allow one to pop up informative windows from the command line:

  • -showData – interactively show the dataset in a new window
  • -showLabels – view the training data and its labels
  • -showResult – displays the experiment result in a new window
  1. The first thing you probably want to enter on the command line is the data you would like to train or train/test on. To do this type –labels and the repository key of the dataset you would like to use. For this experiment you should use the following option: –labels sample1.train.
  2. The next required parameter to specify is either spanProp or spanType. To specify this parameter, type –spanType TYPE. For this dataset TYPE can either be real or spam, so use the following option: -spanType trueName.
  3. Other parameters you may want to specify are:
  • -learner for specifying the learning algorithm
  • -saveAs if you want to save the trained results
  • –help for descriptions and examples of options and parameters. If you are unsure of what learners to use, use the –gui command so that you can see the list of learners and feature extractor available (under trainingParameters). For this tutorial, use:
-learner "new VPHMMLearner(new CollinsPerceptronLearner(1,5), new Recommended.TokenFE(), new InsideOutsideRedution())"
  1. As you can see from this example, the sequenceClassifierLearner, spanFeatureExtractor, and taggingReduction are defined with the learner. If you would like to see the options for these variables, use the –gui command. Once the parameter modification window pops up, click Edit under Parameter Modification and click Edit next to trainingParameters. To see what learners are available, scroll through the pull down list next to learner. Once you have chosen a learner, click the Edit button next to learner to choose your sequenceClassifierLearner, spanFeatureExtractor, and taggingReduction. To edit any of these training parameters, press the Edit button next to them.
  2. Optional parameters to define include –mixup, -embed, and –output. Use the –help command to learn more about these parameters. –output is set to the default _prediction, so you only need to set this parameter if you would like to name the property learned.
  3. Specify other complex parameters on the command line using the –other option. See the Command Line Other Option Tutorial for details.
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