## What changes were proposed in this pull request?
Use SparkSession instead of SQLContext in Python TestSuites
## How was this patch tested?
Existing tests
Author: Sandeep Singh <sandeep@techaddict.me>
Closes#13044 from techaddict/SPARK-15037-python.
## What changes were proposed in this pull request?
The PySpark deserialization has a bug that shows while deserializing all zero sparse vectors. This fix filters out empty string tokens before casting, hence properly stringified SparseVectors successfully get parsed.
## How was this patch tested?
Standard unit-tests similar to other methods.
Author: Arash Parsa <arash@ip-192-168-50-106.ec2.internal>
Author: Arash Parsa <arashpa@gmail.com>
Author: Vishnu Prasad <vishnu667@gmail.com>
Author: Vishnu Prasad S <vishnu667@gmail.com>
Closes#12516 from arashpa/SPARK-14739.
## What changes were proposed in this pull request?
Added windowSize getter/setter to ML/MLlib
## How was this patch tested?
Added test cases in tests.py under both ML and MLlib
Author: Jason Lee <cjlee@us.ibm.com>
Closes#12428 from jasoncl/SPARK-14564.
## What changes were proposed in this pull request?
This fix tries to add binary toggle Param to PySpark HashingTF in ML & MLlib. If this toggle is set, then all non-zero counts will be set to 1.
Note: This fix (SPARK-14238) is extended from SPARK-13963 where Scala implementation was done.
## How was this patch tested?
This fix adds two tests to cover the code changes. One for HashingTF in PySpark's ML and one for HashingTF in PySpark's MLLib.
Author: Yong Tang <yong.tang.github@outlook.com>
Closes#12079 from yongtang/SPARK-14238.
## What changes were proposed in this pull request?
Remove `map`, `flatMap`, `mapPartitions` from python DataFrame, to prepare for Dataset API in the future.
## How was this patch tested?
existing tests
Author: Wenchen Fan <wenchen@databricks.com>
Closes#11445 from cloud-fan/python-clean.
I saw several failures from recent PR builds, e.g., https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/50015/consoleFull. This PR marks the test as ignored and we will fix the flakyness in SPARK-10086.
gliptak Do you know why the test failure didn't show up in the Jenkins "Test Result"?
cc: jkbradley
Author: Xiangrui Meng <meng@databricks.com>
Closes#10909 from mengxr/SPARK-10086.
This is #9263 from gliptak (improving grouping/display of test case results) with a small fix of bisecting k-means unit test.
Author: Gábor Lipták <gliptak@gmail.com>
Author: Xiangrui Meng <meng@databricks.com>
Closes#10850 from mengxr/SPARK-11295.
SPARK-11295 Add packages to JUnit output for Python tests
This improves grouping/display of test case results.
Author: Gábor Lipták <gliptak@gmail.com>
Closes#9263 from gliptak/SPARK-11295.
From the coverage issues for 1.6 : Add Python API for mllib.clustering.BisectingKMeans.
Author: Holden Karau <holden@us.ibm.com>
Closes#10150 from holdenk/SPARK-11937-python-api-coverage-SPARK-11944-python-mllib.clustering.BisectingKMeans.
If initial model passed to GMM is not empty it causes net.razorvine.pickle.PickleException. It can be fixed by converting initialModel.weights to list.
Author: zero323 <matthew.szymkiewicz@gmail.com>
Closes#10644 from zero323/SPARK-12006.
If initial model passed to GMM is not empty it causes `net.razorvine.pickle.PickleException`. It can be fixed by converting `initialModel.weights` to `list`.
Author: zero323 <matthew.szymkiewicz@gmail.com>
Closes#9986 from zero323/SPARK-12006.
Added catch for casting Long to Int exception when PySpark ALS Ratings are serialized. It is easy to accidentally use Long IDs for user/product and before, it would fail with a somewhat cryptic "ClassCastException: java.lang.Long cannot be cast to java.lang.Integer." Now if this is done, a more descriptive error is shown, e.g. "PickleException: Ratings id 1205640308657491975 exceeds max integer value of 2147483647."
Author: Bryan Cutler <bjcutler@us.ibm.com>
Closes#9361 from BryanCutler/als-pyspark-long-id-error-SPARK-10158.
At this moment `SparseVector.__getitem__` executes `np.searchsorted` first and checks if result is in an expected range after that. It is possible to check if index can contain non-zero value before executing `np.searchsorted`.
Author: zero323 <matthew.szymkiewicz@gmail.com>
Closes#9098 from zero323/sparse_vector_getitem_improved.
__gettitem__ method throws IndexError exception when we try to access index after the last non-zero entry
from pyspark.mllib.linalg import Vectors
sv = Vectors.sparse(5, {1: 3})
sv[0]
## 0.0
sv[1]
## 3.0
sv[2]
## Traceback (most recent call last):
## File "<stdin>", line 1, in <module>
## File "/python/pyspark/mllib/linalg/__init__.py", line 734, in __getitem__
## row_ind = inds[insert_index]
## IndexError: index out of bounds
Author: zero323 <matthew.szymkiewicz@gmail.com>
Closes#9009 from zero323/sparse_vector_index_error.
As ```assertEquals``` is deprecated, so we need to change ```assertEquals``` to ```assertEqual``` for existing python unit tests.
Author: Yanbo Liang <ybliang8@gmail.com>
Closes#8814 from yanboliang/spark-10615.
PySpark DenseVector, SparseVector ```__eq__``` method should use semantics equality, and DenseVector can compared with SparseVector.
Implement PySpark DenseVector, SparseVector ```__hash__``` method based on the first 16 entries. That will make PySpark Vector objects can be used in collections.
Author: Yanbo Liang <ybliang8@gmail.com>
Closes#8166 from yanboliang/spark-9793.
Recently, PySpark ML streaming tests have been flaky, most likely because of the batches not being processed in time. Proposal: Replace the use of _ssc_wait (which waits for a fixed amount of time) with a method which waits for a fixed amount of time but can terminate early based on a termination condition method. With this, we can extend the waiting period (to make tests less flaky) but also stop early when possible (making tests faster on average, which I verified locally).
CC: mengxr tdas freeman-lab
Author: Joseph K. Bradley <joseph@databricks.com>
Closes#8087 from jkbradley/streaming-ml-tests.
Python API for the KS-test
Statistics.kolmogorovSmirnovTest(data, distName, *params)
I'm not quite sure how to support the callable function since it is not serializable.
Author: MechCoder <manojkumarsivaraj334@gmail.com>
Closes#7430 from MechCoder/spark-8996 and squashes the following commits:
2dd009d [MechCoder] minor
021d233 [MechCoder] Remove one wrapper and other minor stuff
49d07ab [MechCoder] [SPARK-8996] [MLlib] Python API for Kolmogorov-Smirnov Test
Adding __str__ and __repr__ to DenseMatrix and SparseMatrix
Author: MechCoder <manojkumarsivaraj334@gmail.com>
Closes#6342 from MechCoder/spark-7785 and squashes the following commits:
7b9a82c [MechCoder] Add tests for greater than 16 elements
b88e9dd [MechCoder] Increment limit to 16
1425a01 [MechCoder] Change tests
36bd166 [MechCoder] Change str and repr representation
97f0da9 [MechCoder] zip is same as izip in python3
94ca4b2 [MechCoder] Added doctests and iterate over values instead of colPtrs
b26fa89 [MechCoder] minor
394dde9 [MechCoder] [SPARK-7785] Add __str__ and __repr__ to Matrices
Currently we iterate over indices which can be vectorized.
Author: MechCoder <manojkumarsivaraj334@gmail.com>
Closes#5946 from MechCoder/spark-7203 and squashes the following commits:
034d086 [MechCoder] Vectorize dot calculation for numpy arrays for ndim=2
bce2b07 [MechCoder] fix doctest
fcad0a3 [MechCoder] Remove type checks for list, pyarray etc
0ee5dd4 [MechCoder] Add tests and other isinstance changes
e5f1de0 [MechCoder] [SPARK-7401] Vectorize dot product and sq_dist
Python bindings for StreamingLinearRegressionWithSGD
Author: MechCoder <manojkumarsivaraj334@gmail.com>
Closes#6744 from MechCoder/spark-4127 and squashes the following commits:
d8f6457 [MechCoder] Moved StreamingLinearAlgorithm to pyspark.mllib.regression
d47cc24 [MechCoder] Inherit from StreamingLinearAlgorithm
1b4ddd6 [MechCoder] minor
4de6c68 [MechCoder] Minor refactor
5e85a3b [MechCoder] Add tests for simultaneous training and prediction
fb27889 [MechCoder] Add example and docs
505380b [MechCoder] Add tests
d42bdae [MechCoder] [SPARK-4127] Python bindings for StreamingLinearRegressionWithSGD
Add Python bindings to StreamingLogisticRegressionwithSGD.
No Java wrappers are needed as models are updated directly using train.
Author: MechCoder <manojkumarsivaraj334@gmail.com>
Closes#6849 from MechCoder/spark-3258 and squashes the following commits:
b4376a5 [MechCoder] minor
d7e5fc1 [MechCoder] Refactor into StreamingLinearAlgorithm Better docs
9c09d4e [MechCoder] [SPARK-7633] Python bindings for StreamingLogisticRegressionwithSGD
It is useful to generate linear data for easy testing of linear models and in general. Scala already has it. This is just a wrapper around the Scala code.
Author: MechCoder <manojkumarsivaraj334@gmail.com>
Closes#6715 from MechCoder/generate_linear_input and squashes the following commits:
6182884 [MechCoder] Minor changes
8bda047 [MechCoder] Minor style fixes
0f1053c [MechCoder] [SPARK-8265] Add LinearDataGenerator to pyspark.mllib.utils
Author: Holden Karau <holden@pigscanfly.ca>
Closes#6331 from holdenk/SPARK-7781-GradientBoostedTrees.trainRegressor-missing-max-bins and squashes the following commits:
2894695 [Holden Karau] remove extra blank line
2573e8d [Holden Karau] Update the scala side of the pythonmllibapi and make the test a bit nicer too
3a09170 [Holden Karau] add maxBins to to the train method as well
af7f274 [Holden Karau] Add maxBins to GradientBoostedTrees.trainRegressor and correctly mention the default of 32 in other places where it mentioned 100
[[SPARK-8511] Modify a test to remove a saved model in `regression.py` - ASF JIRA](https://issues.apache.org/jira/browse/SPARK-8511)
Author: Yu ISHIKAWA <yuu.ishikawa@gmail.com>
Closes#6926 from yu-iskw/SPARK-8511 and squashes the following commits:
7cd0948 [Yu ISHIKAWA] Use `shutil.rmtree()` to temporary directories for saving model testings, instead of `os.removedirs()`
4a01c9e [Yu ISHIKAWA] [SPARK-8511][pyspark] Modify a test to remove a saved model in `regression.py`
Python bindings for StreamingKMeans
Will change status to MRG once docs, tests and examples are updated.
Author: MechCoder <manojkumarsivaraj334@gmail.com>
Closes#6499 from MechCoder/spark-4118 and squashes the following commits:
7722d16 [MechCoder] minor style fixes
51052d3 [MechCoder] Doc fixes
2061a76 [MechCoder] Add tests for simultaneous training and prediction Minor style fixes
81482fd [MechCoder] minor
5d9fe61 [MechCoder] predictOn should take into account the latest model
8ab9e89 [MechCoder] Fix Python3 error
a9817df [MechCoder] Better tests and minor fixes
c80e451 [MechCoder] Add ignore_unicode_prefix
ee8ce16 [MechCoder] Update tests, doc and examples
4b1481f [MechCoder] Some changes and tests
d8b066a [MechCoder] [SPARK-4118] [MLlib] [PySpark] Python bindings for StreamingKMeans
Python API for org.apache.spark.mllib.feature.ElementwiseProduct
Author: MechCoder <manojkumarsivaraj334@gmail.com>
Closes#6346 from MechCoder/spark-7605 and squashes the following commits:
79d1ef5 [MechCoder] Consistent and support list / array types
5f81d81 [MechCoder] [SPARK-7605] [MLlib] Python API for ElementwiseProduct
MatrixUDT was recently coded in scala. This has been ported to PySpark
Author: MechCoder <manojkumarsivaraj334@gmail.com>
Closes#6354 from MechCoder/spark-6390 and squashes the following commits:
fc4dc1e [MechCoder] Better error message
c940a44 [MechCoder] Added test
aa9c391 [MechCoder] Add pyUDT to MatrixUDT
62a2a7d [MechCoder] [SPARK-6390] Port MatrixUDT to PySpark
Add
1. Class methods squared_dist
3. parse
4. norm
5. numNonzeros
6. copy
I made a few vectorizations wrt squared_dist and dot as well. I have added support for SparseMatrix serialization in a separate PR (https://github.com/apache/spark/pull/5775) and plan to complete support for Matrices in another PR.
Author: MechCoder <manojkumarsivaraj334@gmail.com>
Closes#5872 from MechCoder/local_linalg_api and squashes the following commits:
a8ff1e0 [MechCoder] minor
ce3e53e [MechCoder] Add error message for parser
1bd3c04 [MechCoder] Robust parser and removed unnecessary methods
f779561 [MechCoder] [SPARK-7328] Pyspark.mllib.linalg.Vectors: Missing items
The following items are added to Python kmeans:
kmeans - setEpsilon, setInitializationSteps
KMeansModel - computeCost, k
Author: Hrishikesh Subramonian <hrishikesh.subramonian@flytxt.com>
Closes#5647 from FlytxtRnD/newPyKmeansAPI and squashes the following commits:
b9e451b [Hrishikesh Subramonian] set seed to fixed value in doc test
5fd3ced [Hrishikesh Subramonian] doc test corrections
20b3c68 [Hrishikesh Subramonian] python 3 fixes
4d4e695 [Hrishikesh Subramonian] added arguments in python tests
21eb84c [Hrishikesh Subramonian] Python Kmeans - setEpsilon, setInitializationSteps, k and computeCost added.
Utilities for pickling and unpickling SparseMatrices using SerDe
Author: MechCoder <manojkumarsivaraj334@gmail.com>
Closes#5775 from MechCoder/spark-7202 and squashes the following commits:
7e689dc [MechCoder] [SPARK-7202] Add SparseMatrixPickler to SerDe
This PR try to speed up some python tests:
```
tests.py 144s -> 103s -41s
mllib/classification.py 24s -> 17s -7s
mllib/regression.py 27s -> 15s -12s
mllib/tree.py 27s -> 13s -14s
mllib/tests.py 64s -> 31s -33s
streaming/tests.py 185s -> 84s -101s
```
Considering python3, the total saving will be 558s (almost 10 minutes) (core, and streaming run three times, mllib runs twice).
During testing, it will show used time for each test file:
```
Run core tests ...
Running test: pyspark/rdd.py ... ok (22s)
Running test: pyspark/context.py ... ok (16s)
Running test: pyspark/conf.py ... ok (4s)
Running test: pyspark/broadcast.py ... ok (4s)
Running test: pyspark/accumulators.py ... ok (4s)
Running test: pyspark/serializers.py ... ok (6s)
Running test: pyspark/profiler.py ... ok (5s)
Running test: pyspark/shuffle.py ... ok (1s)
Running test: pyspark/tests.py ... ok (103s) 144s
```
Author: Reynold Xin <rxin@databricks.com>
Author: Xiangrui Meng <meng@databricks.com>
Closes#5605 from rxin/python-tests-speed and squashes the following commits:
d08542d [Reynold Xin] Merge pull request #14 from mengxr/SPARK-6953
89321ee [Xiangrui Meng] fix seed in tests
3ad2387 [Reynold Xin] Merge pull request #5427 from davies/python_tests
Since sparse matrices now support a isTransposed flag for row major data, DenseMatrices should do the same.
Author: MechCoder <manojkumarsivaraj334@gmail.com>
Closes#5455 from MechCoder/spark-6845 and squashes the following commits:
525c370 [MechCoder] minor
004a37f [MechCoder] Cast boolean to int
151f3b6 [MechCoder] [WIP] Add isTransposed to pickle DenseMatrix
cc0b90a [MechCoder] [SPARK-6845] Add isTranposed flag to DenseMatrix
Author: Elisey Zanko <elisey.zanko@gmail.com>
Closes#5361 from 31z4/spark-6661 and squashes the following commits:
73c5d79 [Elisey Zanko] Python type errors should print type, not object
This PR update PySpark to support Python 3 (tested with 3.4).
Known issue: unpickle array from Pyrolite is broken in Python 3, those tests are skipped.
TODO: ec2/spark-ec2.py is not fully tested with python3.
Author: Davies Liu <davies@databricks.com>
Author: twneale <twneale@gmail.com>
Author: Josh Rosen <joshrosen@databricks.com>
Closes#5173 from davies/python3 and squashes the following commits:
d7d6323 [Davies Liu] fix tests
6c52a98 [Davies Liu] fix mllib test
99e334f [Davies Liu] update timeout
b716610 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
cafd5ec [Davies Liu] adddress comments from @mengxr
bf225d7 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
179fc8d [Davies Liu] tuning flaky tests
8c8b957 [Davies Liu] fix ResourceWarning in Python 3
5c57c95 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
4006829 [Davies Liu] fix test
2fc0066 [Davies Liu] add python3 path
71535e9 [Davies Liu] fix xrange and divide
5a55ab4 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
125f12c [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
ed498c8 [Davies Liu] fix compatibility with python 3
820e649 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
e8ce8c9 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
ad7c374 [Davies Liu] fix mllib test and warning
ef1fc2f [Davies Liu] fix tests
4eee14a [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
20112ff [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
59bb492 [Davies Liu] fix tests
1da268c [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
ca0fdd3 [Davies Liu] fix code style
9563a15 [Davies Liu] add imap back for python 2
0b1ec04 [Davies Liu] make python examples work with Python 3
d2fd566 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
a716d34 [Davies Liu] test with python 3.4
f1700e8 [Davies Liu] fix test in python3
671b1db [Davies Liu] fix test in python3
692ff47 [Davies Liu] fix flaky test
7b9699f [Davies Liu] invalidate import cache for Python 3.3+
9c58497 [Davies Liu] fix kill worker
309bfbf [Davies Liu] keep compatibility
5707476 [Davies Liu] cleanup, fix hash of string in 3.3+
8662d5b [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
f53e1f0 [Davies Liu] fix tests
70b6b73 [Davies Liu] compile ec2/spark_ec2.py in python 3
a39167e [Davies Liu] support customize class in __main__
814c77b [Davies Liu] run unittests with python 3
7f4476e [Davies Liu] mllib tests passed
d737924 [Davies Liu] pass ml tests
375ea17 [Davies Liu] SQL tests pass
6cc42a9 [Davies Liu] rename
431a8de [Davies Liu] streaming tests pass
78901a7 [Davies Liu] fix hash of serializer in Python 3
24b2f2e [Davies Liu] pass all RDD tests
35f48fe [Davies Liu] run future again
1eebac2 [Davies Liu] fix conflict in ec2/spark_ec2.py
6e3c21d [Davies Liu] make cloudpickle work with Python3
2fb2db3 [Josh Rosen] Guard more changes behind sys.version; still doesn't run
1aa5e8f [twneale] Turned out `pickle.DictionaryType is dict` == True, so swapped it out
7354371 [twneale] buffer --> memoryview I'm not super sure if this a valid change, but the 2.7 docs recommend using memoryview over buffer where possible, so hoping it'll work.
b69ccdf [twneale] Uses the pure python pickle._Pickler instead of c-extension _pickle.Pickler. It appears pyspark 2.7 uses the pure python pickler as well, so this shouldn't degrade pickling performance (?).
f40d925 [twneale] xrange --> range
e104215 [twneale] Replaces 2.7 types.InstsanceType with 3.4 `object`....could be horribly wrong depending on how types.InstanceType is used elsewhere in the package--see http://bugs.python.org/issue8206
79de9d0 [twneale] Replaces python2.7 `file` with 3.4 _io.TextIOWrapper
2adb42d [Josh Rosen] Fix up some import differences between Python 2 and 3
854be27 [Josh Rosen] Run `futurize` on Python code:
7c5b4ce [Josh Rosen] Remove Python 3 check in shell.py.
This is the sub-task of SPARK-6254.
Wrap missing method for `StandardScalerModel`.
Author: lewuathe <lewuathe@me.com>
Closes#5310 from Lewuathe/SPARK-6643 and squashes the following commits:
fafd690 [lewuathe] Fix for lint-python
bd31a64 [lewuathe] Merge branch 'master' into SPARK-6643
578f5ee [lewuathe] Remove unnecessary class
a38f155 [lewuathe] Merge master
66bb2ab [lewuathe] Fix typos
82683a0 [lewuathe] [SPARK-6643] Implement StandardScalerModel missing methods
Supporting of SparseMatrix in PySpark.
Author: MechCoder <manojkumarsivaraj334@gmail.com>
Closes#5355 from MechCoder/spark-6577 and squashes the following commits:
7492190 [MechCoder] More readable code for densifying
ea2c54b [MechCoder] Check bounds for indexing
454ef2c [MechCoder] Made the following changes 1. Used convert_to_array for array conversion. 2. Used F order for toArray 3. Minor improvements in speed.
db76caf [MechCoder] Add support for CSR matrix
29653e7 [MechCoder] Renamed indices to rowIndices and indptr to colPtrs
b6384fe [MechCoder] [SPARK-6577] SparseMatrix should be supported in PySpark
... and normL2.
Add test cases to insufficient unit test for `normL1` and `normL2`.
Ref: https://github.com/apache/spark/pull/5359
Author: lewuathe <lewuathe@me.com>
Closes#5374 from Lewuathe/SPARK-6720 and squashes the following commits:
5541b24 [lewuathe] More accurate tests
dc5718c [lewuathe] [SPARK-6720] PySpark MultivariateStatisticalSummary unit test for normL1 and normL2
Add below methods in pyspark for MultivariateStatisticalSummary
- normL1
- normL2
Author: lewuathe <lewuathe@me.com>
Closes#5359 from Lewuathe/SPARK-6262 and squashes the following commits:
cbe439e [lewuathe] Implement missing methods for MultivariateStatisticalSummary
This is the sub-task of SPARK-6254.
Wrap missing method for `Word2Vec` and `Word2VecModel`.
Author: lewuathe <lewuathe@me.com>
Closes#5296 from Lewuathe/SPARK-6615 and squashes the following commits:
f14c304 [lewuathe] Reorder tests
1d326b9 [lewuathe] Merge master
e2bedfb [lewuathe] Modify test cases
afb866d [lewuathe] [SPARK-6615] Python API for Word2Vec
davies
Author: Xiangrui Meng <meng@databricks.com>
Closes#5318 from mengxr/SPARK-6660 and squashes the following commits:
0f66ec2 [Xiangrui Meng] recognize object arrays
ad8c42f [Xiangrui Meng] add a test for SPARK-6660
Support indexing in DenseMatrices in PySpark
Author: MechCoder <manojkumarsivaraj334@gmail.com>
Closes#5232 from MechCoder/SPARK-6576 and squashes the following commits:
a735078 [MechCoder] Change bounds
a062025 [MechCoder] Matrices are stored in column order
7917bc1 [MechCoder] [SPARK-6576] DenseMatrix in PySpark should support indexing
This is the sub-task of SPARK-6254.
Wrapping IDFModel `idf` member function for pyspark.
Author: lewuathe <lewuathe@me.com>
Closes#5264 from Lewuathe/SPARK-6598 and squashes the following commits:
1dc522c [lewuathe] [SPARK-6598] Python API for IDFModel
Weight parameters must be initialized correctly even when numpy array is passed as initial weights.
Author: lewuathe <lewuathe@me.com>
Closes#5101 from Lewuathe/SPARK-6421 and squashes the following commits:
7795201 [lewuathe] Fix lint-python errors
21d4fe3 [lewuathe] Fix init logic of weights
Similar to `MatrixFactorizaionModel`, we only need wrappers to support save/load for tree models in Python.
jkbradley
Author: Xiangrui Meng <meng@databricks.com>
Closes#4854 from mengxr/SPARK-6097 and squashes the following commits:
4586a4d [Xiangrui Meng] fix more typos
8ebcac2 [Xiangrui Meng] fix python style
91172d8 [Xiangrui Meng] fix typos
201b3b9 [Xiangrui Meng] update user guide
b5158e2 [Xiangrui Meng] support tree model save/load in PySpark/MLlib
