cumulative_sum¶
- cumulative_sum(x: array, /, *, axis: int | None = None, dtype: dtype | None = None, include_initial: bool = False) array ¶
Calculates the cumulative sum of elements in the input array
x
.- Parameters:
x (array) – input array. Should have a numeric data type.
axis (Optional[int]) –
axis along which a cumulative sum must be computed. If
axis
is negative, the function must determine the axis along which to compute a cumulative sum by counting from the last dimension.If
x
is a one-dimensional array, providing anaxis
is optional; however, ifx
has more than one dimension, providing anaxis
is required.dtype (Optional[dtype]) –
data type of the returned array. If
None
, the returned array must have the same data type asx
, unlessx
has an integer data type supporting a smaller range of values than the default integer data type (e.g.,x
has anint16
oruint32
data type and the default integer data type isint64
). In those latter cases:if
x
has a signed integer data type (e.g.,int16
), the returned array must have the default integer data type.if
x
has an unsigned integer data type (e.g.,uint16
), the returned array must have an unsigned integer data type having the same number of bits as the default integer data type (e.g., if the default integer data type isint32
, the returned array must have auint32
data type).
If the data type (either specified or resolved) differs from the data type of
x
, the input array should be cast to the specified data type before computing the sum (rationale: thedtype
keyword argument is intended to help prevent overflows). Default:None
.include_initial (bool) – boolean indicating whether to include the initial value as the first value in the output. By convention, the initial value must be the additive identity (i.e., zero). Default:
False
.
- Returns:
out (array) – an array containing the cumulative sums. The returned array must have a data type as described by the
dtype
parameter above.Let
N
be the size of the axis along which to compute the cumulative sum. The returned array must have a shape determined according to the following rules:if
include_initial
isTrue
, the returned array must have the same shape asx
, except the size of the axis along which to compute the cumulative sum must beN+1
.if
include_initial
isFalse
, the returned array must have the same shape asx
.
Notes
Special Cases
For both real-valued and complex floating-point operands, special cases must be handled as if the operation is implemented by successive application of
add()
.New in version 2023.12.