[SPARK-16214] [Examples] fix the denominator of SparkPi

[yanghaogn]

What changes were proposed in this pull request?

reduce the denominator of SparkPi by 1

How was this patch tested?

integration tests

[yanghaogn]

As the iteration number is n - 1, the denominator would also be n,

[HyukjinKwon]

Get ready to receive a comment suggesting following https://cwiki.apache.org/confluence/display/SPARK/Contributing+to+Spark..

I believe this is not a [MINOR] because it is not virtually the same.

trivial changes, where the what should change is virtually the same as the how it should change do not require a JIRA.

[srowen]

Nah @HyukjinKwon I think this is a simple fix that's self-contained here. Either the iterations or the estimate formula is wrong here and that's all there is to it. (0 until n) would be fine too.

[srowen]

@yanghaogn since you already made a JIRA, connect it in the title please. It is not resolved

[srowen]

Jenkins test this please

[yanghaogn]

@srowen It's been related now

[srowen]

Not quite, see https://cwiki.apache.org/confluence/display/SPARK/Contributing+to+Spark and other PRs

[SparkQA]

Test build #61261 has finished for PR 13910 at commit f91e55e.

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

[yanghaogn]

As explained in #2874

The max size of the input seq was Int.MaxValue - 1

This change may cause a bug. For the input is very big and It can be treated as not a problem. But then it's hard to understand the logic if users have not read the #2874

[srowen]

I see, maybe better to just fix the denominator then.

[srowen]

Jenkins retest this please

[SparkQA]

Test build #61268 has finished for PR 13910 at commit 1cfbea2.

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

[srowen]

Merged to master/2.0/1.6