[SPARK-14900][ML]:spark.ml classification metrics should include accuracy

[wangmiao1981]

What changes were proposed in this pull request?

(Please fill in changes proposed in this fix)
Add accuracy to MulticlassMetrics class and add corresponding code in MulticlassClassificationEvaluator.

How was this patch tested?

(Please explain how this patch was tested. E.g. unit tests, integration tests, manual tests)
Scala Unit tests in ml.evaluation

[SparkQA]

Test build #57680 has finished for PR 12882 at commit e7202ba.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[srowen]

See comment on JIRA; we might even deprecate precision?

[wangmiao1981]

@srowen Thanks for your review! I think it makes a lot sense of deprecating "precision" with "accuracy" as I got confused when I tried to add accuracy yesterday. I will make the changes.

[SparkQA]

Test build #57776 has finished for PR 12882 at commit 46ba842.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • * (equals to accuracy for multiclass classifier

[SparkQA]

Test build #57777 has finished for PR 12882 at commit 42d7f3d.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #57848 has finished for PR 12882 at commit 5b7a7fd.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[srowen]

You need to leave the @Since annotation though. I might also not say it will be removed for sure in 2.1. May be removed.

[SparkQA]

Test build #57917 has finished for PR 12882 at commit ac66a7a.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #57918 has finished for PR 12882 at commit f511982.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • * (equals to precision for multiclass classifier

[wangmiao1981]

@srowen Any comments on the change? Thanks!

[srowen]

I think this is OK as a 'rename'. I wouldn't mind hearing from @mengxr as a double check

[srowen]

Sorry @wangmiao1981 can we do one more thing -- let's have all the deprecated methods call accuracy. Right now this (simple) expression is duplicated. And, note in precision's docs that it equals accuracy.

[wangmiao1981]

@srowen I will make the suggested changes.

Thanks!

[SparkQA]

Test build #58515 has finished for PR 12882 at commit 11132db.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[wangmiao1981]

@srowen I have made the changes. Thanks!

[srowen]

Merged to master/2.0