MLModel.CompileModel(NSUrl, NSError) Method

Definition

Namespace:

CoreML

Assembly:

Xamarin.iOS.dll

Compiles the model at modelUrl.

[Foundation.Export("compileModelAtURL:error:")]
public static Foundation.NSUrl CompileModel (Foundation.NSUrl modelUrl, out Foundation.NSError error);

static member CompileModel : Foundation.NSUrl *  -> Foundation.NSUrl

Parameters

modelUrl

NSUrl

A URL to a model to compile.

error

NSError

On failure, the error that occurred.

Returns

NSUrl

Attributes

ExportAttribute

Remarks

This is an expensive function. Execution time varies depending on the model size, but developers should run this method on a background thread and take steps to avoid the need to run this method repeatedly.

The following example shows how a developer can download a model, compile it, and move the compiled model into the app's permanent storage:

NSUrl CompileModel(string modelName)
{
	var downloadedFile = modelName + ".mlmodel";
	var fileUrl = NSUrl.FromFilename(downloadedFile);
	NSError err = null;
	var compiledUrl = MLModel.CompileModel(fileUrl, out err);
	if (err != null)
	{
		throw new Exception(err.ToString());
	}
	return compiledUrl;
}

NSUrl StoreModel(NSUrl sourceUrl)
{
	var fileManager = NSFileManager.DefaultManager;
	NSError err = null;
	var appSupportDirectory = fileManager.GetUrl(NSSearchPathDirectory.ApplicationSupportDirectory, NSSearchPathDomain.User, sourceUrl, true, out err);
	if (err != null)
	{
		throw new Exception(err.ToString());
	}

	// Create a permanent URL in appSupportDirectory
	var destinationUrl = appSupportDirectory.Append(sourceUrl.LastPathComponent, true);
	NSUrl resultingUrl = null;

	var destPath = destinationUrl.AbsoluteString;
	// If the compiled model directory exists, replace it
	if (System.IO.Directory.Exists(destinationUrl.Path))
	{
		fileManager.Replace(destinationUrl, sourceUrl, null, NSFileManagerItemReplacementOptions.None, out resultingUrl, out err);
	}
	else
	{
		fileManager.Copy(sourceUrl, destinationUrl, out err);
	}
	if (err != null)
	{
		throw new Exception(err.ToString());
	}
	return resultingUrl;
}

private async Task<NSUrl> DownloadAndStoryCoreMLModelAsync()
{
  var modelName = "SomeModel";
	var sourceUrl ="https://Contoso.org/SomeModel.mlmodel";
	using (var wc = new WebClient())
	{
		await wc.DownloadFileTaskAsync(sourceUrl, modelName +".mlmodel");
		var compiledModelPath = CompileModel(modelName);
		var finalPath = StoreModel(compiledModelPath);
    return finalPath;
	}
}