This RFC requests to include a new API in the array API specification for the purpose of computing the cumulative sum.

Overview

Based on array comparison data, the API is available in all the libraries in the PyData ecosystem.

Prior art

• NumPy: https://numpy.org/doc/stable/reference/generated/numpy.cumsum.html
• PyTorch: https://pytorch.org/docs/stable/generated/torch.cumsum.html
• MXNet: https://mxnet.apache.org/versions/1.6/api/r/docs/api/mx.nd.cumsum.html
• TensorFlow: https://www.tensorflow.org/api_docs/python/tf/math/cumsum

Proposal:

def cumsum(x: array, /, *, axis: Optional[Union[int, Tuple[int, ...]]] = None, dtype: Optional[dtype] = None) -> array

• dtype kwarg is for consistency with sum et al

cc @oleksandr-pavlyk