Github user srowen commented on a diff in the pull request:
https://github.com/apache/spark/pull/17793#discussion_r113874652
--- Diff: mllib/src/main/scala/org/apache/spark/ml/recommendation/ALS.scala
---
@@ -791,32 +813,43 @@ object ALS extends DefaultParamsReadable[ALS] with
Logging {
checkpointInterval: Int = 10,
seed: Long = 0L)(
implicit ord: Ordering[ID]): (RDD[(ID, Array[Float])], RDD[(ID,
Array[Float])]) = {
+
require(!ratings.isEmpty(), s"No ratings available from $ratings")
require(intermediateRDDStorageLevel != StorageLevel.NONE,
"ALS is not designed to run without persisting intermediate RDDs.")
+
val sc = ratings.sparkContext
+
+ // Precompute the rating dependencies of each partition
val userPart = new ALSPartitioner(numUserBlocks)
val itemPart = new ALSPartitioner(numItemBlocks)
- val userLocalIndexEncoder = new
LocalIndexEncoder(userPart.numPartitions)
- val itemLocalIndexEncoder = new
LocalIndexEncoder(itemPart.numPartitions)
- val solver = if (nonnegative) new NNLSSolver else new CholeskySolver
val blockRatings = partitionRatings(ratings, userPart, itemPart)
.persist(intermediateRDDStorageLevel)
val (userInBlocks, userOutBlocks) =
makeBlocks("user", blockRatings, userPart, itemPart,
intermediateRDDStorageLevel)
- // materialize blockRatings and user blocks
- userOutBlocks.count()
+ userOutBlocks.count() // materialize blockRatings and user blocks
val swappedBlockRatings = blockRatings.map {
case ((userBlockId, itemBlockId), RatingBlock(userIds, itemIds,
localRatings)) =>
((itemBlockId, userBlockId), RatingBlock(itemIds, userIds,
localRatings))
}
val (itemInBlocks, itemOutBlocks) =
makeBlocks("item", swappedBlockRatings, itemPart, userPart,
intermediateRDDStorageLevel)
- // materialize item blocks
- itemOutBlocks.count()
+ itemOutBlocks.count() // materialize item blocks
+
+ // Encoders for storing each user/item's partition ID and index within
its partition using a
--- End diff --
This is probably fine but I tend to avoid moving code around unless it
really helps -- this minimizes things like back-port merge conflict problems.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
