Method: Numo::NArray.concatenate

Defined in:

lib/numo/narray/extra.rb

.concatenate(arrays, axis: 0) ⇒ Object

Examples:

a = Numo::DFloat[[1, 2], [3, 4]]
# => Numo::DFloat#shape=[2,2]
# [[1, 2],
#  [3, 4]]

b = Numo::DFloat[[5, 6]]
# => Numo::DFloat#shape=[1,2]
# [[5, 6]]

Numo::NArray.concatenate([a,b],axis:0)
# => Numo::DFloat#shape=[3,2]
# [[1, 2],
#  [3, 4],
#  [5, 6]]

Numo::NArray.concatenate([a,b.transpose], axis:1)
# => Numo::DFloat#shape=[2,3]
# [[1, 2, 5],
#  [3, 4, 6]]

# File 'lib/numo/narray/extra.rb', line 426

def concatenate(arrays,axis:0)
  klass = (self==NArray) ? NArray.array_type(arrays) : self
  nd = 0
  arrays = arrays.map do |a|
    case a
    when NArray
      # ok
    when Numeric
      a = klass[a]
    when Array
      a = klass.cast(a)
    else
      raise TypeError,"not Numo::NArray: #{a.inspect[0..48]}"
    end
    if a.ndim > nd
      nd = a.ndim
    end
    a
  end
  if axis < 0
    axis += nd
  end
  if axis < 0 || axis >= nd
    raise ArgumentError,"axis is out of range"
  end
  new_shape = nil
  sum_size = 0
  arrays.each do |a|
    a_shape = a.shape
    if nd != a_shape.size
      a_shape = [1]*(nd-a_shape.size) + a_shape
    end
    sum_size += a_shape.delete_at(axis)
    if new_shape
      if new_shape != a_shape
        raise ShapeError,"shape mismatch"
      end
    else
      new_shape = a_shape
    end
  end
  new_shape.insert(axis,sum_size)
  result = klass.zeros(*new_shape)
  lst = 0
  refs = [true] * nd
  arrays.each do |a|
    fst = lst
    lst = fst + (a.shape[axis-nd]||1)
    if lst > fst
      refs[axis] = fst...lst
      result[*refs] = a
    end
  end
  result
end