# cumsum¶

dragon.math.cumsum(
inputs,
axis=0,
exclusive=False,
reverse=False,
**kwargs
)[source]

Compute the cumulative sum of elements along the given axis.

axis could be negative:

# A negative axis is the last-k axis
x = dragon.constant([[1, 2, 3], [4, 5, 6]])
print(dragon.math.cumsum(x, axis=1))   # [[1, 3, 6], [4, 9, 15]]
print(dragon.math.cumsum(x, axis=-1))  # Equivalent


Use exclusive to exclude the top element:

x = dragon.constant([1, 2, 3])
print(dragon.math.cumsum(x, exclusive=True))  # [0, 1, 3]


Use reverse to reverse the cumulative direction:

x = dragon.constant([1, 2, 3])
print(dragon.math.cumsum(x))  # [1, 3, 6]
print(dragon.math.cumsum(x, reverse=True))  # [6, 5, 3]
print(dragon.math.cumsum(x, exclusive=True, reverse=True))  # [5, 3, 0]

Parameters:
• inputs (dragon.Tensor) – The input tensor.
• axis (int, optional, default=0) – The axis to cumulate.
• exclusive (bool, optional, default=False) – True to exclude the top element.
• reverse (bool, optional, default=False) – True to cumulate in a reverse direction.
Returns:

dragon.Tensor – The output tensor.