using System;

namespace NumSharp

{

public static partial class np

{

/// <summary>

/// Join a sequence of arrays along a new axis.

/// The axis parameter specifies the index of the new axis in the dimensions of the result.

/// For example, if axis=0 it will be the first dimension and if axis=-1 it will be the last dimension.

/// </summary>

/// <param name="arrays">Each array must have the same shape.</param>

/// <param name="axis">The axis in the result array along which the input arrays are stacked.</param>

/// <returns>The stacked array has one more dimension than the input arrays.</returns>

/// <remarks>https://docs.scipy.org/doc/numpy/reference/generated/numpy.stack.html</remarks>

public static NDArray stack(NDArray[] arrays, int axis = 0)

{

if (arrays == null)

throw new ArgumentNullException(nameof(arrays));

if (arrays.Length == 0)

throw new ArgumentException("Value cannot be an empty collection.", nameof(arrays));

arrays = np.atleast_1d(arrays); //handle scalars

var first = arrays[0];

arrays[0] = np.expand_dims(first, axis);

for (int i = 1; i < arrays.Length; i++)

{

var curr = arrays[i];

if (curr.Shape != first.Shape)

throw new InvalidOperationException("all input arrays must have the same shape");

arrays[i] = np.expand_dims(curr, axis);

}

return np.concatenate(arrays, axis);

}

}

}