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https://issues.apache.org/jira/browse/ARROW-11567?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Antoine Pitrou resolved ARROW-11567.
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Fix Version/s: 4.0.0
Resolution: Fixed
Issue resolved by pull request 9604
[https://github.com/apache/arrow/pull/9604]
> [C++][Compute] Variance kernel has precision issue
> --------------------------------------------------
>
> Key: ARROW-11567
> URL: https://issues.apache.org/jira/browse/ARROW-11567
> Project: Apache Arrow
> Issue Type: Bug
> Components: C++
> Affects Versions: 3.0.0
> Reporter: Yibo Cai
> Assignee: Yibo Cai
> Priority: Major
> Labels: pull-request-available
> Fix For: 4.0.0
>
> Time Spent: 1.5h
> Remaining Estimate: 0h
>
> For long arrays, variance kernel is not accurate compared with numpy. See
> below example.
> {noformat}
> In [1]: import numpy as np
> In [2]: import pyarrow.compute as pc
> In [3]: t = np.arange(321000, dtype='float')
> In [4]: np.var(t)
> Out[4]: 8586749999.916667
> In [5]: pc.variance(t)
> Out[5]: <pyarrow.DoubleScalar: 8586749999.899047>
> {noformat}
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