[I] [C++][Compute] Rank function considers NaNs and nulls equal [arrow]

[via GitHub]

pitrou opened a new issue, #45193:
URL: https://github.com/apache/arrow/issues/45193

   ### Describe the bug, including details regarding any error messages, 
version, and platform.
   
   Expected (NaNs and nulls are distinct, ordered according to 
`null_placement`):
   ```python
   >>> a = pa.array([1, None, math.nan, 2, math.nan, None])
   >>> pc.rank(a, tiebreaker='min', null_placement='at_end')
   <pyarrow.lib.UInt64Array object at 0x7f168295ca00>
   [
     1,
     5,
     3,
     2,
     3,
     5
   ]
   >>> pc.rank(a, tiebreaker='min', null_placement='at_start')
   <pyarrow.lib.UInt64Array object at 0x7f1682845600>
   [
     5,
     1,
     3,
     6,
     3,
     1
   ]
   ```
   
   Actual (NaNs and nulls are considered ties):
   ```python
   >>> pc.rank(a, tiebreaker='min', null_placement='at_end')
   <pyarrow.lib.UInt64Array object at 0x7f1682951660>
   [
     1,
     3,
     3,
     2,
     3,
     3
   ]
   >>> pc.rank(a, tiebreaker='min', null_placement='at_start')
   <pyarrow.lib.UInt64Array object at 0x7f1682845600>
   [
     5,
     1,
     1,
     6,
     1,
     1
   ]
   ```
   
   
   ### Component(s)
   
   C++


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: issues-unsubscr...@arrow.apache.org.apache.org

For queries about this service, please contact Infrastructure at:
us...@infra.apache.org