Github user sueann commented on a diff in the pull request: https://github.com/apache/spark/pull/17090#discussion_r104036563 --- Diff: mllib/src/test/scala/org/apache/spark/ml/recommendation/ALSSuite.scala --- @@ -594,6 +595,95 @@ class ALSSuite model.setColdStartStrategy(s).transform(data) } } + + private def getALSModel = { + val spark = this.spark + import spark.implicits._ + + val userFactors = Seq( + (0, Array(6.0f, 4.0f)), + (1, Array(3.0f, 4.0f)), + (2, Array(3.0f, 6.0f)) + ).toDF("id", "features") + val itemFactors = Seq( + (3, Array(5.0f, 6.0f)), + (4, Array(6.0f, 2.0f)), + (5, Array(3.0f, 6.0f)), + (6, Array(4.0f, 1.0f)) + ).toDF("id", "features") + val als = new ALS().setRank(2) + new ALSModel(als.uid, als.getRank, userFactors, itemFactors) + .setUserCol("user") + .setItemCol("item") + } + + test("recommendForAllUsers with k < num_items") { + val topItems = getALSModel.recommendForAllUsers(2) + assert(topItems.count() == 3) + assert(topItems.columns.contains("user")) + + val expected = Map( + 0 -> Array(Row(3, 54f), Row(4, 44f)), + 1 -> Array(Row(3, 39f), Row(5, 33f)), + 2 -> Array(Row(3, 51f), Row(5, 45f)) + ) + checkRecommendations(topItems, expected, "item") + } + + test("recommendForAllUsers with k = num_items") { + val topItems = getALSModel.recommendForAllUsers(4) + assert(topItems.count() == 3) + assert(topItems.columns.contains("user")) + + val expected = Map( + 0 -> Array(Row(3, 54f), Row(4, 44f), Row(5, 42f), Row(6, 28f)), + 1 -> Array(Row(3, 39f), Row(5, 33f), Row(4, 26f), Row(6, 16f)), + 2 -> Array(Row(3, 51f), Row(5, 45f), Row(4, 30f), Row(6, 18f)) + ) + checkRecommendations(topItems, expected, "item") + } + + test("recommendForAllItems with k < num_users") { + val topUsers = getALSModel.recommendForAllItems(2) + assert(topUsers.count() == 4) + assert(topUsers.columns.contains("item")) + + val expected = Map( + 3 -> Array(Row(0, 54f), Row(2, 51f)), + 4 -> Array(Row(0, 44f), Row(2, 30f)), + 5 -> Array(Row(2, 45f), Row(0, 42f)), + 6 -> Array(Row(0, 28f), Row(2, 18f)) + ) + checkRecommendations(topUsers, expected, "user") + } + + test("recommendForAllItems with k = num_users") { + val topUsers = getALSModel.recommendForAllItems(3) + assert(topUsers.count() == 4) + assert(topUsers.columns.contains("item")) + + val expected = Map( + 3 -> Array(Row(0, 54f), Row(2, 51f), Row(1, 39f)), + 4 -> Array(Row(0, 44f), Row(2, 30f), Row(1, 26f)), + 5 -> Array(Row(2, 45f), Row(0, 42f), Row(1, 33f)), + 6 -> Array(Row(0, 28f), Row(2, 18f), Row(1, 16f)) + ) + checkRecommendations(topUsers, expected, "user") + } + + private def checkRecommendations( + topK: DataFrame, + expected: Map[Int, Array[Row]], + dstColName: String): Unit = { + assert(topK.columns.contains("recommendations")) + topK.collect().foreach { row => + val id = row.getInt(0) + val recs = row.getAs[WrappedArray[Row]]("recommendations") + assert(recs === expected(id)) + assert(recs(0).fieldIndex(dstColName) == 0) + assert(recs(0).fieldIndex("rating") == 1) --- End diff -- Actually nevermind. Either way is committing to an incompatible API so the name one seems preferable.
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