jgperrin / net.jgp.books.spark.ch05 Goto Github PK

I wondered why I got an error on piComputeClusterApp.py. There's a clustername called spark://un:7077 in it, instead of local[]. I think you forgot to change it to local? I've tried the code with local[] and that works.

spark = SparkSession.builder.appName("PySparkPi on a cluster")
.master("spark://un:7077").getOrCreate()
#.master("local[*]").getOrCreate()

First, thank you for the book! It's so great!

Second, and maybe I'm misunderstanding, but aren't we trying to take the square root below, not just their addition? As written, it seems closer to variance.

Shouldn't it be this?

return (sqrt(x * x + y * y) <= 1) ? 1 : 0;

After importing java.lang.Math, that change compiles but it doesn't seem to get the answer any closer to or further away from 3.14159..., but maybe it's the randomly created data set...