public static NDArray StandardizeSingleArray(NDArray x)
        {
            if (x == null)
            {
                return(null);
            }
            else if (K.IsTensor(x))
            {
                var shape = x.Shape;
                if (shape == null || shape[0] == 0)
                {
                    throw new Exception(String.Format("When feeding symbolic tensors to a model, we expect thetensors to have a static batch size. Got tensor with shape: {0}", shape.ToString()));
                }
                return(x);
            }
            else if (x.Dimension == 1)
            {
                x = nd.ExpandDims(x, 1);
            }

            return(x);
        }
        public static NDArrayList StandardizeInputData(NDArrayList data, string[] names, Shape[] shapes = null, bool check_batch_axis = true, string exception_prefix = "", bool check_last_layer_shape = true)
        {
            if (names == null)
            {
                if (data != null && data.Length == 0)
                {
                    throw new Exception("Error when checking model " + exception_prefix + ": expected no data");
                }

                return(new NDArrayList());
            }

            if (data == null)
            {
                return((from _ in Enumerable.Range(0, names.Length)
                        select new NDArray()).ToList());
            }

            data = (from x in data
                    select StandardizeSingleArray(x)).ToList();

            if (data.Length != names.Length)
            {
                if (data[0].Shape != null)
                {
                    throw new Exception("Error when checking model " + exception_prefix + ": the list of Numpy arrays that you are passing to your model is not the size the model expected. Expected to see " + names.Length.ToString() + " array(s), but instead got the following list of " + data.Length.ToString());
                }
                else if (names.Length > 1)
                {
                    throw new Exception("Error when checking model " + exception_prefix + ": you are passing a list as input to your model, but the model expects a list of " + names.Length.ToString());
                }
            }

            // Check shapes compatibility.
            if (shapes != null)
            {
                foreach (var i in Enumerable.Range(0, names.Length))
                {
                    if (shapes[i] != null && !K.IsTensor(data[i]))
                    {
                        var data_shape = data[i].Shape;
                        var shape      = shapes[i];
                        if (data[i].Dimension != shape.Dimension)
                        {
                            throw new Exception("Error when checking " + exception_prefix + ": expected " + names[i] + " to have " + shape.Dimension.ToString() + " dimensions, but got array with shape " + data_shape.ToString());
                        }
                        if (!check_batch_axis)
                        {
                            data_shape = data_shape[1];
                            shape      = shape[1];
                        }
                        foreach (var _tup_1 in Enumerable.Zip(data_shape.Data, shape.Data, (d, s) => { return(d, s); }))
                        {
                            var dim     = _tup_1.Item1;
                            var ref_dim = _tup_1.Item2;
                            if (ref_dim != dim && ref_dim > 0)
                            {
                                // ignore shape difference in last layer only if loss is
                                // multi_hot_sparse_categorical_crossentropy,
                                // last layer can only be dense or activation layer
                                if (!check_last_layer_shape && (names[i].ToLower().StartsWith("dense") || names[i].ToLower().StartsWith("activation")))
                                {
                                    continue;
                                }

                                throw new Exception("Error when checking " + exception_prefix + ": expected " + names[i] + " to have shape " + shape.ToString() + " but got array with shape " + data_shape.ToString());
                            }
                        }
                    }
                }
            }

            return(data);
        }