1 | .. _Calibration Plot: |
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2 | |
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3 | Calibration Plot |
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4 | ================ |
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5 | |
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6 | .. image:: ../icons/CalibrationPlot.png |
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7 | |
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8 | Shows the match between the classifiers' probability predictions and actual |
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9 | class probabilities. |
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10 | |
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11 | Signals |
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12 | ------- |
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13 | |
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14 | Inputs: |
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15 | - Evaluation Results (orngTest.ExperimentResults) |
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16 | Results of classifiers' tests on data |
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17 | |
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18 | |
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19 | Outputs: |
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20 | - None |
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21 | |
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22 | Description |
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23 | ----------- |
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24 | |
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25 | Calibration plot plots the class probabilities against those predicted by |
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26 | the classifier(s). |
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27 | |
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28 | .. image:: images/CalibrationPlot.png |
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29 | |
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30 | Option :obj:`Target class` chooses the positive class. In case there are more |
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31 | than two classes, the widget considers all other classes as a single, negative |
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32 | class. If the test results contain more than one classifier, the user can |
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33 | choose which curves she or he wants to see plotted. |
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34 | |
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35 | The diagonal represents the optimal behaviour; the close the classifier gets, |
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36 | the more accurate its predictions. |
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37 | |
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38 | If :obj:`Show rug` is enable, ticks at the bottom and the top of the graph |
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39 | represents negative and positive examples (respectively). Their position |
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40 | corresponds to classifier's probability prediction and the color shows the |
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41 | classifier. On the bottom of the graph, the points to the left are those |
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42 | which are (correctly) assigned a low probability of the target class, and |
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43 | those to the right are incorrectly assigned high probabilities. On the top |
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44 | of the graph, the instances to the right are correctly assigned hight |
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45 | probabilities and vice versa. |
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46 | |
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47 | Example |
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48 | ------- |
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49 | |
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50 | At the moment, the only widget which give the right type of the signal |
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51 | needed by the Calibration Plot is :ref:`Test Learners`. The Calibration Plot |
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52 | will hence always follow Test Learners and, since it has no outputs, no other |
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53 | widgets follow it. Here is a typical example. |
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54 | |
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55 | .. image:: images/ROCLiftCalibration-Schema.png |
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