[SPARK-7604] [MLlib] Python API for PCA and PCAModel

[yanboliang]

Python API for PCA and PCAModel

[SparkQA]

Test build #33231 has finished for PR 6315 at commit 4d9d121.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • class PCAModel(JavaVectorTransformer):
  • class PCA(object):

[davies]

This is the default behavior, so you could not have transform() in PCAModel. (just remove transform() here)

[SparkQA]

Test build #33343 has finished for PR 6315 at commit 1d58734.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • class PCAModel(JavaVectorTransformer):
  • class PCA(object):

[yanboliang]

@jkbradley @mengxr

[jkbradley]

LGTM sorry for the delay!
I'll rerun tests since it's been a while, before merging

[jkbradley]

test this please

[SparkQA]

Test build #35403 has finished for PR 6315 at commit 1d58734.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • class PCAModel(JavaVectorTransformer):
  • class PCA(object):

[jkbradley]

Merging with master

Thanks!