/// <summary>
/// Stack arrays in sequence horizontally
/// </summary>
/// <param name="nps"></param>
/// <returns></returns>
public NDArray hstack <T>(params NDArray[] nps)
{
if (nps == null || nps.Length == 0)
{
throw new Exception("Input arrays can not be empty");
}
var npAll = new NDArray[nps.Length + 1];
npAll[0] = this;
for (int idx = 0; idx < nps.Length; idx++)
{
if (nps[0].Storage.Shape != nps[idx].Storage.Shape)
{
throw new Exception("Arrays mush have same shapes");
}
else
{
npAll[idx + 1] = nps[idx];
}
}
var nd = new NDArray(typeof(T));
// easy 1D case
if (this.ndim == 1)
{
var list1D = new List <T>();
for (int idx = 0; idx < npAll.Length; idx++)
{
list1D.AddRange(npAll[idx].Data <T>().ToList());
}
nd = np.array(list1D.ToArray(), this.dtype);
}
else
{
int total = npAll[0].ndim == 1 ? 1 : npAll[0].shape[0];
var list = new List <T>();
for (int i = 0; i < total; i++)
{
for (int k = 0; k < npAll.Length; k++)
{
var pufferShape = new Shape(npAll[k].shape);
int pageSize = npAll[k].ndim == 1 ? npAll[k].shape[0] : pufferShape.Strides[0];
for (int j = i * pageSize; j < (i + 1) * pageSize; j++)
{
var ele = npAll[k].Data <T>()[j];
list.Add(ele);
}
}
}
int[] shapes = new int[npAll[0].shape.Length];
npAll[0].shape.CopyTo(shapes, 0);
if (shapes.Length == 1)
{
shapes[0] *= npAll.Length;
}
else
{
shapes[1] = npAll.Sum(x => x.shape[1]);
}
nd.Storage.Allocate(new Shape(shapes));
nd.Storage.SetData(list.ToArray());
}
return(nd);
}