Crashing with MLMultiArray

gistfile1.swift

 
    func resize(to: CGFloat) -> UIImage {
        
        let scale = to / self.size.width
        let newHeight = self.size.height * scale
        UIGraphicsBeginImageContext(CGSize(width: to, height: newHeight))
        self.draw(in: CGRect(x: 0, y: 0, width: to, height: newHeight))
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        
        return newImage!
    }
    
    func pixelData() -> [UInt8]? {
        let size = self.size
        let dataSize = size.width * size.height * 4
        var pixelData = [UInt8](repeating: 0, count: Int(dataSize))
        let colorSpace = CGColorSpaceCreateDeviceRGB()
        let context = CGContext(data: &pixelData,
                                width: Int(size.width),
                                height: Int(size.height),
                                bitsPerComponent: 8,
                                bytesPerRow: 4 * Int(size.width),
                                space: colorSpace,
                                bitmapInfo: CGImageAlphaInfo.noneSkipLast.rawValue)
        guard let cgImage = self.cgImage else { return nil }
        context?.draw(cgImage, in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
        
        return pixelData
    }
    
    func preprocess(image: UIImage) -> MLMultiArray? {
        
        guard let pixels = image.resize(to: 224)
                                .pixelData()?
                                .map({ (Double($0) / 255.0 - 0.5) * 2 }) else {
            return nil
        }
        
        guard let array = try? MLMultiArray(shape: [3, 224, 224], dataType: .double) else {
            return nil
        }
        
        let r = pixels.enumerated().filter { $0.offset % 4 == 0 }.map { $0.element }
        let g = pixels.enumerated().filter { $0.offset % 4 == 1 }.map { $0.element }
        let b = pixels.enumerated().filter { $0.offset % 4 == 2 }.map { $0.element }
        let combination = r + g + b
        
        for (index, element) in combination.enumerated() {
            let number = NSNumber(value: element)
            array[index] = number
        }
        
        return array
        
    }

Awesome! thanks for sharing