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# MLSoundClassifier.ModelParameters.ModelAlgorithmType.transferLearning(featureExtractor:classifier:)

An algorithm that leverages the knowledge of a general-purpose model built into the operating system.

```
case transferLearning(featureExtractor: MLSoundClassifier.ModelParameters.FeatureExtractorType, classifier: MLSoundClassifier.ModelParameters.ClassifierType)
```

## Parameters

`featureExtractor`

The extractor type the algorithm uses to detect features from the audio data.

`classifier`

The model type the algorithm uses to classify audio data.

## Discussion

You typically use this transfer-learning algorithm to train an object detector in these situations:

- Your training dataset has a limited number of examples.
- You prefer your object detector’s Core ML model file to be as small as possible.

---

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