### What changes were proposed in this pull request?
This PR aims to add `StorageLevel.DISK_ONLY_3` as a built-in `StorageLevel`.
### Why are the changes needed?
In a YARN cluster, HDFS uaually provides storages with replication factor 3. So, we can save the result to HDFS to get `StorageLevel.DISK_ONLY_3` technically. However, disaggregate clusters or clusters without storage services are rising. Previously, in that situation, the users were able to use similar `MEMORY_AND_DISK_2` or a user-created `StorageLevel`. This PR aims to support those use cases officially for better UX.
### Does this PR introduce _any_ user-facing change?
Yes. This provides a new built-in option.
### How was this patch tested?
Pass the GitHub Action or Jenkins with the revised test cases.
Closes#29331 from dongjoon-hyun/SPARK-32517.
Authored-by: Dongjoon Hyun <dongjoon@apache.org>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
### What changes were proposed in this pull request?
This proposes to port old PySpark migration guide to new PySpark docs.
### Why are the changes needed?
Better documentation.
### Does this PR introduce _any_ user-facing change?
No. Documentation only.
### How was this patch tested?
Generated document locally.
<img width="1521" alt="Screen Shot 2020-08-07 at 1 53 20 PM" src="https://user-images.githubusercontent.com/68855/89687618-672e7700-d8b5-11ea-8f29-67a9ab271fa8.png">
Closes#29385 from viirya/SPARK-32191.
Authored-by: Liang-Chi Hsieh <viirya@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
### What changes were proposed in this pull request?
This PR proposes to write the main page of PySpark documentation. The base work is finished at https://github.com/apache/spark/pull/29188.
### Why are the changes needed?
For better usability and readability in PySpark documentation.
### Does this PR introduce _any_ user-facing change?
Yes, it creates a new main page as below:
### How was this patch tested?
Manually built the PySpark documentation.
```bash
cd python
make clean html
```
Closes#29320 from HyukjinKwon/SPARK-32507.
Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
### What changes were proposed in this pull request?
Add training summary to MultilayerPerceptronClassificationModel...
### Why are the changes needed?
so that user can get the training process status, such as loss value of each iteration and total iteration number.
### Does this PR introduce _any_ user-facing change?
Yes
MultilayerPerceptronClassificationModel.summary
MultilayerPerceptronClassificationModel.evaluate
### How was this patch tested?
new tests
Closes#29250 from huaxingao/mlp_summary.
Authored-by: Huaxin Gao <huaxing@us.ibm.com>
Signed-off-by: Sean Owen <srowen@gmail.com>
### What changes were proposed in this pull request?
This PR proposes to redesign the PySpark documentation.
I made a demo site to make it easier to review: https://hyukjin-spark.readthedocs.io/en/stable/reference/index.html.
Here is the initial draft for the final PySpark docs shape: https://hyukjin-spark.readthedocs.io/en/latest/index.html.
In more details, this PR proposes:
1. Use [pydata_sphinx_theme](https://github.com/pandas-dev/pydata-sphinx-theme) theme - [pandas](https://pandas.pydata.org/docs/) and [Koalas](https://koalas.readthedocs.io/en/latest/) use this theme. The CSS overwrite is ported from Koalas. The colours in the CSS were actually chosen by designers to use in Spark.
2. Use the Sphinx option to separate `source` and `build` directories as the documentation pages will likely grow.
3. Port current API documentation into the new style. It mimics Koalas and pandas to use the theme most effectively.
One disadvantage of this approach is that you should list up APIs or classes; however, I think this isn't a big issue in PySpark since we're being conservative on adding APIs. I also intentionally listed classes only instead of functions in ML and MLlib to make it relatively easier to manage.
### Why are the changes needed?
Often I hear the complaints, from the users, that current PySpark documentation is pretty messy to read - https://spark.apache.org/docs/latest/api/python/index.html compared other projects such as [pandas](https://pandas.pydata.org/docs/) and [Koalas](https://koalas.readthedocs.io/en/latest/).
It would be nicer if we can make it more organised instead of just listing all classes, methods and attributes to make it easier to navigate.
Also, the documentation has been there from almost the very first version of PySpark. Maybe it's time to update it.
### Does this PR introduce _any_ user-facing change?
Yes, PySpark API documentation will be redesigned.
### How was this patch tested?
Manually tested, and the demo site was made to show.
Closes#29188 from HyukjinKwon/SPARK-32179.
Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
