[REVIEW]Handle index when dispatching __array_function__ and __array_ufunc__ to cupy for cudf.Series

[VibhuJawa]

This pr adds index handling when dispatching to cupy functions with __ufunc__ and __array_function__ for cudf.Series.

This PR does the following:

• Adds index handling for __ufunc__ and __array_function (when being dispatched to cupy)
• Adds test to ensure the same results as pandas with aligned index
• Adds tests for appropriate errors non-aligned index
• Removs support for list inputs (should not have been supported initially too)

Please note that I am unsure how to handle list inputs here.
The problem being solved here is below:

With this PR #6839 we get the correct index when we do the following:

>>> cudf_s1 = cudf.Series(data=[-1, 2, 3, 0], index=[2, 3, 1, 0])
>>> cudf_s2 = cudf.Series(data=[-1, -2, 3, 0], index=[2, 3, 1, 0])
>>> o = np.logaddexp(cudf_s1, cudf_s2)
>>> o.index
Int64Index([2, 3, 1, 0], dtype='int64')
>>> print(o)
2   -0.306853
3    2.018150
1    3.693147
0    0.693147
dtype: float64

On Master we get:

>>> cudf_s1 = cudf.Series(data=[-1, 2, 3, 0], index=[2, 3, 1, 0])
>>> cudf_s2 = cudf.Series(data=[-1, -2, 3, 0], index=[2, 3, 1, 0])
>>> o = np.logaddexp(cudf_s1, cudf_s2)
>>> o.index
RangeIndex(start=0, stop=4, step=1)
>>> print(o)
0   -0.306853
1    2.018150
2    3.693147
3    0.693147
dtype: float64

[GPUtester]

Please update the changelog in order to start CI tests.

View the gpuCI docs here.

[codecov]

Codecov Report

Merging #6839 (7a12226) into branch-0.17 (cdc53b7) will increase coverage by 0.01%.
The diff coverage is 93.75%.

@@               Coverage Diff               @@
##           branch-0.17    #6839      +/-   ##
===============================================
+ Coverage        81.94%   81.95%   +0.01%     
===============================================
  Files               96       96              
  Lines            16164    16168       +4     
===============================================
+ Hits             13246    13251       +5     
+ Misses            2918     2917       -1     

Impacted Files	Coverage Δ
python/cudf/cudf/utils/utils.py	84.93% <93.75%> (+0.68%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update cdc53b7...7a12226. Read the comment docs.

[VibhuJawa]

Removed this as the index is undefined when dispatching to cupyfor these functions.

[VibhuJawa]

rerun tests

[brandon-b-miller]

In the process of looking this over - I am building this branch to better understand the problem being solved here.

[VibhuJawa]

In the process of looking this over - I am building this branch to better understand the problem being solved here.

Below might help. With this PR we get the correct index on the following:

>>> cudf_s1 = cudf.Series(data=[-1, 2, 3, 0], index=[2, 3, 1, 0])
>>> cudf_s2 = cudf.Series(data=[-1, -2, 3, 0], index=[2, 3, 1, 0])
>>> o = np.logaddexp(cudf_s1, cudf_s2)
>>> o.index
Int64Index([2, 3, 1, 0], dtype='int64')
>>> print(o)
2   -0.306853
3    2.018150
1    3.693147
0    0.693147
dtype: float64

On Master we get:

>>> cudf_s1 = cudf.Series(data=[-1, 2, 3, 0], index=[2, 3, 1, 0])
>>> cudf_s2 = cudf.Series(data=[-1, -2, 3, 0], index=[2, 3, 1, 0])
>>> o = np.logaddexp(cudf_s1, cudf_s2)
>>> o.index
RangeIndex(start=0, stop=4, step=1)
>>> print(o)
0   -0.306853
1    2.018150
2    3.693147
3    0.693147
dtype: float64

[isVoid]

Just some general questions.

[VibhuJawa]

All reviews have been addressed, this should be ready for another review.

CC: @brandon-b-miller , @isVoid

[brandon-b-miller]

One last question otherwise LGTM.

[VibhuJawa]

@isVoid, Please let me know if there is anything else I need to address.

[isVoid]

lgtm!