## What changes were proposed in this pull request?
This is a follow-up PR of #16800
When doing SPARK-19456, we found that "" should be consider a NULL column name and should not be set. aggregationDepth should be exposed as an expert parameter.
## How was this patch tested?
Existing tests.
Author: wm624@hotmail.com <wm624@hotmail.com>
Closes#16945 from wangmiao1981/svc.
## What changes were proposed in this pull request?
Linear SVM classifier is newly added into ML and python API has been added. This JIRA is to add R side API.
Marked as WIP, as I am designing unit tests.
## How was this patch tested?
Please review http://spark.apache.org/contributing.html before opening a pull request.
Author: wm624@hotmail.com <wm624@hotmail.com>
Closes#16800 from wangmiao1981/svc.
## What changes were proposed in this pull request?
The `coefficients` component in model summary should be 'matrix' but the underlying structure is indeed list. This affects several models except for 'AFTSurvivalRegressionModel' which has the correct implementation. The fix is to first `unlist` the coefficients returned from the `callJMethod` before converting to matrix. An example illustrates the issues:
```
data(iris)
df <- createDataFrame(iris)
model <- spark.glm(df, Sepal_Length ~ Sepal_Width, family = "gaussian")
s <- summary(model)
> str(s$coefficients)
List of 8
$ : num 6.53
$ : num -0.223
$ : num 0.479
$ : num 0.155
$ : num 13.6
$ : num -1.44
$ : num 0
$ : num 0.152
- attr(*, "dim")= int [1:2] 2 4
- attr(*, "dimnames")=List of 2
..$ : chr [1:2] "(Intercept)" "Sepal_Width"
..$ : chr [1:4] "Estimate" "Std. Error" "t value" "Pr(>|t|)"
> s$coefficients[, 2]
$`(Intercept)`
[1] 0.4788963
$Sepal_Width
[1] 0.1550809
```
This shows that the underlying structure of coefficients is still `list`.
felixcheung wangmiao1981
Author: actuaryzhang <actuaryzhang10@gmail.com>
Closes#16730 from actuaryzhang/sparkRCoef.
## What changes were proposed in this pull request?
SparkR ```mllib.R``` is getting bigger as we add more ML wrappers, I'd like to split it into multiple files to make us easy to maintain:
* mllib_classification.R
* mllib_clustering.R
* mllib_recommendation.R
* mllib_regression.R
* mllib_stat.R
* mllib_tree.R
* mllib_utils.R
Note: Only reorg, no actual code change.
## How was this patch tested?
Existing tests.
Author: Yanbo Liang <ybliang8@gmail.com>
Closes#16312 from yanboliang/spark-18862.
