On Fri, Aug 18, 2023 at 4:59 AM Ronald van Elburg < r.a.j.van.elburg@hetnet.nl> wrote:
I was trying to get a feel for how often the work around occurs. I found three clear examples in Scipy and one unclear case. One case in holoviews. Two in numpy. One from soundappraisal's code base.
See also my comment from back in 2020: https://github.com/numpy/numpy/pull/14542#issuecomment-586494608 Anyone interested in this enhancement is encouraged to review the discussion in that pull request (https://github.com/numpy/numpy/pull/14542), and an earlier issue from 2015: https://github.com/numpy/numpy/issues/6044 Warren
Next to prepending to the output, I also see prepending to the input as a workaround.
Some examples of workarounds:
scipy: (prepending to the output)
scipy/scipy/sparse/construct.py:
'''Python row_offsets = np.append(0, np.cumsum(brow_lengths)) col_offsets = np.append(0, np.cumsum(bcol_lengths)) '''
scipy/scipy/sparse/dia.py:
'''Python indptr = np.zeros(num_cols + 1, dtype=idx_dtype) indptr[1:offset_len+1] = np.cumsum(mask.sum(axis=0)) '''
scipy/scipy/sparse/csgraph/_tools.pyx:
'''Python indptr = np.zeros(N + 1, dtype=ITYPE) indptr[1:] = mask.sum(1).cumsum() '''
Not sure whether this is also an example:
scipy/scipy/stats/_hypotests_pythran.py '''Python # Now fill in the values. We cannot use cumsum, unfortunately. val = 0.0 if minj == 0 else 1.0 for jj in range(maxj - minj): j = jj + minj val = (A[jj + minj - lastminj] * i + val * j) / (i + j) A[jj] = val '''
holoviews: (prepending to the input)
'''Python # We add a zero in the begging for the cumulative sum points = np.zeros((areas_in_radians.shape[0] + 1)) points[1:] = areas_in_radians points = points.cumsum() '''
numpy (prepending to the input):
numpy/numpy/lib/_iotools.py :
'''Python idx = np.cumsum([0] + list(delimiter)) '''
numpy/numpy/lib/histograms.py
'''Python cw = np.concatenate((zero, sw.cumsum())) '''
soundappraisal own code: (prepending to the output)
'''Python def get_cumulativepixelareas(whiteboard): whiteboard['cumulativepixelareas'] = \ np.concatenate((np.array([0, ]), np.cumsum(whiteboard['pixelareas']))) return True ''' _______________________________________________ NumPy-Discussion mailing list -- numpy-discussion@python.org To unsubscribe send an email to numpy-discussion-leave@python.org https://mail.python.org/mailman3/lists/numpy-discussion.python.org/ Member address: warren.weckesser@gmail.com