/// <summary>
        /// Routine to train the network
        /// </summary>
        /// <param name="cnnProject">The CNN project.</param>
        /// <param name="numberOfRounds">The number of training rounds.</param>
        public void TrainPattern(CNNProject cnnProject, long numberOfTrainingRounds)
        {
            // 1. preparation - both project's imageLists generalized images to the shuffled trainingItem-list
            #region 1. preparation
            List<TrainingItem> trainingItemList = new List<TrainingItem>();

            #region fills the trainingItemList

            ImageList imgList;
            bool matching;
            for (int i = 0; i < 2; i++)
            {

                // at first we include the matching images
                if (i == 0)
                {
                    imgList = cnnProject.Matching;
                    matching = true;
                }
                // and then the not matching images
                else
                {
                    imgList = cnnProject.Matching;
                    matching = false;
                }

                foreach (Image img in imgList.Images)
                {
                    // generalizes the image
                    Image generalizedImg = ImageHandling.GeneralizeImage(img);
                    trainingItemList.Add(new TrainingItem(generalizedImg, matching));
                }
            }
            #endregion

            // filled list gets shuffled
            // (maybe this optimizes the result)
            StaticClasses.Shuffle<TrainingItem>(trainingItemList);
            #endregion

            // 2. build of training data items and add it to the helper
            #region 2. trainingItem

            // used later on to create the training thread
            NetworkHelper helper = new NetworkHelper(_network);

            foreach (TrainingItem trainingItem in trainingItemList)
            {

                Image img = trainingItem.Image;
                ArrayList arryListInput;
                #region fills arryListInput
                // Converts an image of any size to a pattern that can be feed to the network.
                ImageProcessingHelper imgHelper = new ImageProcessingHelper();
                //note: this is a (monochrome) collection of 0's and 1's !!
                arryListInput = imgHelper.ArrayListFromImage(img);

                if (img.Width * img.Height != _network.InputLayer.Count)
                {
                    throw new InvalidInputException("The number of pixels in the input image doesn't match the number of input layer neurons!", null);
                }

                #region Debugging
                /*
                // Convert an arrayList by rounding each value to a pattern of 0s and 1s
                PatternProcessingHelper patHelper = new PatternProcessingHelper();
                String tmpPatern = patHelper.PatternFromArraylist(tmpImgList);
                Debug.WriteLine("Added : " + tmpPatern);
                */
                #endregion
                #endregion

                ArrayList arryListOutput;
                #region fills arryListOutput
                arryListOutput = new ArrayList();
                // true is going to be a single 1, false a single 0
                arryListOutput.Add(trainingItem.Matching ? 1 : 0);
                #endregion

                // a training data item is used for a single training round
                TrainingData trainingDataItem = new TrainingData(arryListInput, arryListOutput);

                // this could be also used; one training round directly
                //_network.TrainNetwork(trainingDataItem);

                helper.AddTrainingData(trainingDataItem);
            }
            #endregion

            // Let's go!
            _trainStart = DateTime.Now;

            // 3. training
            #region  3. training

            // ShowProgress delegate
            helper.TrainingProgress += new NetworkHelper.TrainingProgressEventHandler(ShowProgress);

            // Start training
            // --- here we are going to wait --
            helper.Train(numberOfTrainingRounds, true); // <--

            // releasing
            helper.TrainingProgress -= new NetworkHelper.TrainingProgressEventHandler(ShowProgress);

            // show message box
            if (StopTrainingSilently == false)
            {

                MessageBox.Show("Training of the neuronal network completed at " + DateTime.Now,
                                "Training Completed",
                                MessageBoxButtons.OK,
                                MessageBoxIcon.Information);
            }

            #endregion
        }