numpy 1.22.4 Pypi GitHub Homepage
Other Docs
NotesParametersReturnsBackRef
cumsum(a, axis=None, dtype=None, out=None)

Notes

Arithmetic is modular when using integer types, and no error is raised on overflow.

cumsum(a)[-1] may not be equal to sum(a) for floating-point values since sum may use a pairwise summation routine, reducing the roundoff-error. See sum for more information.

Parameters

a : array_like

Input array.

axis : int, optional

Axis along which the cumulative sum is computed. The default (None) is to compute the cumsum over the flattened array.

dtype : dtype, optional

Type of the returned array and of the accumulator in which the elements are summed. If dtype is not specified, it defaults to the dtype of a, unless a has an integer dtype with a precision less than that of the default platform integer. In that case, the default platform integer is used.

out : ndarray, optional

Alternative output array in which to place the result. It must have the same shape and buffer length as the expected output but the type will be cast if necessary. See ufuncs-output-type for more details.

Returns

cumsum_along_axis : ndarray.

A new array holding the result is returned unless :None:None:`out` is specified, in which case a reference to :None:None:`out` is returned. The result has the same size as a, and the same shape as a if :None:None:`axis` is not None or a is a 1-d array.

Return the cumulative sum of the elements along a given axis.

See Also

diff

Calculate the n-th discrete difference along given axis.

sum

Sum array elements.

trapz

Integration of array values using the composite trapezoidal rule.

Examples

>>> a = np.array([[1,2,3], [4,5,6]])
... a array([[1, 2, 3], [4, 5, 6]])
>>> np.cumsum(a)
array([ 1,  3,  6, 10, 15, 21])
>>> np.cumsum(a, dtype=float)     # specifies type of output value(s)
array([  1.,   3.,   6.,  10.,  15.,  21.])
>>> np.cumsum(a,axis=0)      # sum over rows for each of the 3 columns
array([[1, 2, 3],
       [5, 7, 9]])
>>> np.cumsum(a,axis=1)      # sum over columns for each of the 2 rows
array([[ 1,  3,  6],
       [ 4,  9, 15]])

cumsum(b)[-1] may not be equal to sum(b)

>>> b = np.array([1, 2e-9, 3e-9] * 1000000)
... b.cumsum()[-1] 1000000.0050045159
>>> b.sum()
1000000.0050000029
See :

Back References

The following pages refer to to this document either explicitly or contain code examples using this.

skimage.exposure.exposure.cumulative_distribution numpy.nancumsum numpy.sum numpy.ma.core.cumsum dask.array.reductions.nancumsum numpy.ma.core.MaskedArray.cumsum scipy.integrate._quadrature.cumulative_trapezoid numpy.diff numpy.trapz dask.array.reductions.cumsum dask.array.core.Array.cumsum

Local connectivity graph

Hover to see nodes names; edges to Self not shown, Caped at 50 nodes.

Using a canvas is more power efficient and can get hundred of nodes ; but does not allow hyperlinks; , arrows or text (beyond on hover)

SVG is more flexible but power hungry; and does not scale well to 50 + nodes.

All aboves nodes referred to, (or are referred from) current nodes; Edges from Self to other have been omitted (or all nodes would be connected to the central node "self" which is not useful). Nodes are colored by the library they belong to, and scaled with the number of references pointing them


GitHub : /numpy/core/fromnumeric.py#2495
type: <class 'function'>
Commit: