Github user ajaysaini725 commented on a diff in the pull request:
https://github.com/apache/spark/pull/18281#discussion_r127557890
--- Diff:
mllib/src/test/scala/org/apache/spark/ml/classification/OneVsRestSuite.scala ---
@@ -101,6 +101,50 @@ class OneVsRestSuite extends SparkFunSuite with
MLlibTestSparkContext with Defau
assert(expectedMetrics.confusionMatrix ~== ovaMetrics.confusionMatrix
absTol 400)
}
+ test("one-vs-rest: tuning parallelism does not change output") {
+ val numClasses = 3
+ val ovaPar1 = new OneVsRest()
+ .setClassifier(new LogisticRegression)
+
+ val ovaModelPar1 = ovaPar1.fit(dataset)
+
+ val transformedDatasetPar1 = ovaModelPar1.transform(dataset)
+
+ val ovaResultsPar1 = transformedDatasetPar1.select("prediction",
"label").rdd.map {
+ row => (row.getDouble(0), row.getDouble(1))
+ }
+
+ val ovaPar2 = new OneVsRest()
+ .setClassifier(new LogisticRegression)
+ .setParallelism(2)
+
+ val ovaModelPar2 = ovaPar2.fit(dataset)
+
+ val transformedDatasetPar2 = ovaModelPar2.transform(dataset)
+
+ val ovaResultsPar2 = transformedDatasetPar2.select("prediction",
"label").rdd.map {
+ row => (row.getDouble(0), row.getDouble(1))
+ }
+
+ val metricsPar1 = new MulticlassMetrics(ovaResultsPar1)
+ val metricsPar2 = new MulticlassMetrics(ovaResultsPar2)
+ assert(metricsPar1.confusionMatrix == metricsPar2.confusionMatrix)
+
+ for (i <- 0 until ovaModelPar1.models.length) {
+ var foundCloseCoeffs = false
+ val currentCoeffs = ovaModelPar1.models(i)
+
.asInstanceOf[LogisticRegressionModel].coefficients
+ for (j <- 0 until ovaModelPar2.models.length) {
--- End diff --
Because of the parallelism the order in which the models are written to the
array might be different between runs. As a result, it is necessary to compare
all pairs of models in the arrays not just models at the same indices.
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