Github user mallman commented on a diff in the pull request:
https://github.com/apache/spark/pull/165#discussion_r10714229
--- Diff:
mllib/src/main/scala/org/apache/spark/mllib/recommendation/ALS.scala ---
@@ -187,21 +189,39 @@ class ALS private (
}
}
- for (iter <- 1 to iterations) {
- // perform ALS update
- logInfo("Re-computing I given U (Iteration %d/%d)".format(iter,
iterations))
- // YtY / XtX is an Option[DoubleMatrix] and is only required for the
implicit feedback model
- val YtY = computeYtY(users)
- val YtYb = ratings.context.broadcast(YtY)
- products = updateFeatures(users, userOutLinks, productInLinks,
partitioner, rank, lambda,
- alpha, YtYb)
- logInfo("Re-computing U given I (Iteration %d/%d)".format(iter,
iterations))
- val XtX = computeYtY(products)
- val XtXb = ratings.context.broadcast(XtX)
- users = updateFeatures(products, productOutLinks, userInLinks,
partitioner, rank, lambda,
- alpha, XtXb)
+ if (implicitPrefs) {
+ for (iter <- 1 to iterations) {
+ // perform ALS update
+ logInfo("Re-computing I given U (Iteration %d/%d)".format(iter,
iterations))
+ // Persist users because it will be called twice.
+ users.persist()
+ val YtY = Some(sc.broadcast(computeYtY(users)))
+ val previousProducts = products
+ products = updateFeatures(users, userOutLinks, productInLinks,
partitioner, rank, lambda,
+ alpha, YtY)
+ previousProducts.unpersist()
+ logInfo("Re-computing U given I (Iteration %d/%d)".format(iter,
iterations))
+ products.persist()
+ val XtX = Some(sc.broadcast(computeYtY(products)))
+ val previousUsers = users
+ users = updateFeatures(products, productOutLinks, userInLinks,
partitioner, rank, lambda,
+ alpha, XtX)
+ previousUsers.unpersist()
+ }
+ } else {
+ for (iter <- 1 to iterations) {
+ // perform ALS update
+ logInfo("Re-computing I given U (Iteration %d/%d)".format(iter,
iterations))
+ products = updateFeatures(users, userOutLinks, productInLinks,
partitioner, rank, lambda,
+ alpha, YtY = None)
+ logInfo("Re-computing U given I (Iteration %d/%d)".format(iter,
iterations))
+ users = updateFeatures(products, productOutLinks, userInLinks,
partitioner, rank, lambda,
+ alpha, YtY = None)
+ }
}
+ products.persist()
--- End diff --
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