GitHub user dbtsai opened a pull request:
https://github.com/apache/spark/pull/6109
[SPARK-7568][ML] ml.LogisticRegression doesn't output the right prediction
This is because we regularize the intercept before which effectively
regularizing
less on the weights. Now, we follow the R's standard without regularizing
the intercept,
so we need to decrease the regularization.
BTW, we need to implement efficient cross validation soon to help users to
pick up lambda.
with lambda = 0.001 in current LOR implementation, the prediction is
```
(4, spark i j k) --> prob=[0.1596407738787411,0.8403592261212589],
prediction=1.0
(5, l m n) --> prob=[0.8378325685476612,0.16216743145233883], prediction=0.0
(6, mapreduce spark) --> prob=[0.6693126798261013,0.3306873201738986],
prediction=0.0
(7, apache hadoop) --> prob=[0.9821575333444208,0.01784246665557917],
prediction=0.0
```
and the training accuracy is
```
(0, a b c d e spark) --> prob=[0.0021342419881406746,0.9978657580118594],
prediction=1.0
(1, b d) --> prob=[0.9959176174854043,0.004082382514595685], prediction=0.0
(2, spark f g h) --> prob=[0.0014541569986711233,0.9985458430013289],
prediction=1.0
(3, hadoop mapreduce) --> prob=[0.9982978367343561,0.0017021632656438518],
prediction=0.0
```
Before the LOR change (the implementation that regularizes the intercept),
the prediction is
```
(4, spark i j k) --> prob=[0.18764577263047177,0.8123542273695282],
prediction=1.0
(5, l m n) --> prob=[0.6508848199790638,0.3491151800209362], prediction=0.0
(6, mapreduce spark) --> prob=[0.561585214970727,0.43841478502927295],
prediction=0.0
(7, apache hadoop) --> prob=[0.9118076920593474,0.08819230794065264],
prediction=0.0
```
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/dbtsai/spark lor-example
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/6109.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 #6109
----
commit 8f40ccd38ccc42a06a86f56e2cfc6893daf8dc10
Author: DB Tsai <[email protected]>
Date: 2015-05-13T04:38:55Z
first commit
----
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