On Fri, Aug 18, 2023 at 4:59 AM Ronald van Elburg < r.a.j.van.elb...@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-le...@python.org > https://mail.python.org/mailman3/lists/numpy-discussion.python.org/ > Member address: warren.weckes...@gmail.com >
_______________________________________________ NumPy-Discussion mailing list -- numpy-discussion@python.org To unsubscribe send an email to numpy-discussion-le...@python.org https://mail.python.org/mailman3/lists/numpy-discussion.python.org/ Member address: arch...@mail-archive.com
