---
title: "init(validationData:batchSize:maximumIterations:predictionWindowSize:)"
framework: Create ML
role: symbol
role_heading: Initializer
platforms: [macOS 10.15+]
path: "createml/mlactivityclassifier/modelparameters-swift.struct/init(validationdata:batchsize:maximumiterations:predictionwindowsize:)"
---

# init(validationData:batchSize:maximumIterations:predictionWindowSize:)

Creates a set of activity classifier parameters that includes a validation dataset in a data source.

## Declaration

```swift
init(validationData: MLActivityClassifier.DataSource, batchSize: Int? = 32, maximumIterations: Int? = 10, predictionWindowSize: Int? = 100)
```

## Parameters

- `validationData`: An doc://com.apple.createml/documentation/CreateML/MLActivityClassifier/DataSource instance that contains a validation dataset.
- `batchSize`: The number of activity entries the training session uses for each of its training iterations.
- `maximumIterations`: The largest number of training iterations the training session can use.
- `predictionWindowSize`: The number of time increments the training session uses to train an activity classifier.

## See Also

### Creating parameters

- [init(validation:batchSize:maximumIterations:predictionWindowSize:)](createml/mlactivityclassifier/modelparameters-swift.struct/init(validation:batchsize:maximumiterations:predictionwindowsize:).md)
- [MLActivityClassifier.ModelParameters.Validation](createml/mlactivityclassifier/modelparameters-swift.struct/validation-swift.enum.md)