Demo Unhelpful Error

accordDivByZeroError.linq

<Query Kind="Program">
  <Reference>&lt;RuntimeDirectory&gt;\System.Drawing.dll</Reference>
  <NuGetReference>Accord.Imaging</NuGetReference>
  <Namespace>Accord.Imaging</Namespace>
  <Namespace>System.Drawing</Namespace>
  <Namespace>System.Drawing.Imaging</Namespace>
  <Namespace>Accord.MachineLearning</Namespace>
</Query>

void Main()
{
	var trainingDirectory = @"PATH TO UNZIPPED `train` DIRECTORY";

	var images = LabeledImages.FromDirectory(trainingDirectory).ToArray();

	var binarySplit = new BinarySplit(32);

	var bow = new BagOfVisualWords(binarySplit);

	bow.Compute(images.Select(i => i.Item).Take(50).ToArray());
	
	bow.Dump();
}

public interface ILabeledItem<T> {
	string Category { get; }
	
	T Item { get; }
}

public class LabeledImages : ILabeledItem<Bitmap> {
	public LabeledImages(string category, string filename) {
		Category = category;
		Filename = filename;
	}

	public string Category { get; private set; }

	public string Filename { get; private set; }

	public Bitmap Item {
		get {
			using (var sourceImage = Image.FromFile(Filename)) {
				var targetImage = new Bitmap(sourceImage.Width, sourceImage.Height, PixelFormat.Format32bppArgb);
				using (var canvas = Graphics.FromImage(targetImage)) {
					canvas.DrawImageUnscaled(sourceImage, 0, 0);
				}
				return targetImage;
			}
		}
	}

	public static IEnumerable<LabeledImages> FromDirectory(string path) {
		return Directory.EnumerateDirectories(path)
			.SelectMany(dir => Directory.EnumerateFiles(dir)
				.Select(file => new LabeledImages(Path.GetFileName(dir), file)));
	}
}