GitHub user naftaliharris opened a pull request:
https://github.com/apache/spark/pull/1652
Avoid numerical instability
This avoids basically doing 1 - 1, for example:
```python
>>> from math import exp
>>> margin = -40
>>> 1 - 1 / (1 + exp(margin))
0.0
>>> exp(margin) / (1 + exp(margin))
4.248354255291589e-18
>>>
```
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/naftaliharris/spark patch-2
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/1652.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #1652
----
commit 0d55a9fae74edf990a087463a52b81ef196862a2
Author: Naftali Harris <naftalihar...@gmail.com>
Date: 2014-07-30T06:46:30Z
Avoid numerical instability
This avoids basically doing 1 - 1, for example:
>>> from math import exp
>>> margin = -40
>>> 1 - 1 / (1 + exp(margin))
0.0
>>> exp(margin) / (1 + exp(margin))
4.248354255291589e-18
>>>
----
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