srowen commented on a change in pull request #28045: [SPARK-31283][ML] Simplify
ChiSq by adding a common method
URL: https://github.com/apache/spark/pull/28045#discussion_r399821160
##########
File path:
mllib/src/main/scala/org/apache/spark/mllib/stat/test/ChiSqTest.scala
##########
@@ -94,127 +94,73 @@ private[spark] object ChiSqTest extends Logging {
methodName: String = PEARSON.name): Array[ChiSqTestResult] = {
data.flatMap { case LabeledPoint(label, features) =>
require(features.size == numFeatures)
- features.iterator.map { case (col, value) =>
- (col, (value, label))
- }
+ features.iterator.map { case (col, value) => (col, (label, value)) }
}.aggregateByKey(new OpenHashMap[(Double, Double), Long])(
- seqOp = { case (count, t) =>
- count.changeValue(t, 1L, _ + 1L)
- count
+ seqOp = { case (counts, t) =>
+ counts.changeValue(t, 1L, _ + 1L)
+ counts
},
- combOp = { case (count1, count2) =>
- count2.iterator.foreach { case (t, c) =>
- count1.changeValue(t, c, _ + c)
- }
- count1
- }
- ).map { case (col, count) =>
- val label2Index =
count.iterator.map(_._1._2).toArray.distinct.sorted.zipWithIndex.toMap
- val numLabels = label2Index.size
- if (numLabels > maxCategories) {
- throw new SparkException(s"Chi-square test expect factors (categorical
values) but "
- + s"found more than $maxCategories distinct label values.")
- }
-
- val value2Index =
count.iterator.map(_._1._1).toArray.distinct.sorted.zipWithIndex.toMap
- val numValues = value2Index.size
- if (numValues > maxCategories) {
- throw new SparkException(s"Chi-square test expect factors (categorical
values) but "
- + s"found more than $maxCategories distinct values in column $col.")
+ combOp = { case (counts1, counts2) =>
+ counts2.foreach { case (t, c) => counts1.changeValue(t, c, _ + c) }
Review comment:
OK, so the iterator isn't helping here if just used with foreach. OK.
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