[ https://issues.apache.org/jira/browse/MAHOUT-1810?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15200134#comment-15200134 ]
Andrew Palumbo commented on MAHOUT-1810: ---------------------------------------- Thanks, I will check back in with you on the mapBlock join fix when I'm more focused on this issue. I have MAHOUT-1815 more in my head right now, but I am suspecting that Flink partitioning has something to do with all of our major bugs. I don't believe that the Flink engine supports zips for DataSets. In the case of Flink AewB a join is always done via {{DataSet.coGroup}}: {code} val rowsA = A.asRowWise.ds val rowsB = B.asRowWise.ds implicit val kTag = op.keyClassTag val res: DataSet[(K, Vector)] = rowsA .coGroup(rowsB) .where(0) .equalTo(0) { (left, right, out: Collector[(K, Vector)]) => (left.toIterable.headOption, right.toIterable.headOption) match { case (Some((idx, a)), Some((_, b))) => out.collect((idx, function(a, b))) case (None, Some(b)) => out.collect(b) case (Some(a), None) => out.collect(a) case (None, None) => throw new RuntimeException("At least one side of the co group " + "must be non-empty.") } } {code} > Failing test in flink-bindings: A %*% B Identically partitioned > --------------------------------------------------------------- > > Key: MAHOUT-1810 > URL: https://issues.apache.org/jira/browse/MAHOUT-1810 > Project: Mahout > Issue Type: Bug > Reporter: Andrew Palumbo > Assignee: Andrew Palumbo > Priority: Blocker > Fix For: 0.12.0 > > > the {{A %*% B, Identically Partitioned}} test in the Flink RLikeDrmOpsSuite > fails. This test failure likely indicates an issue with Flink's > Checkpointing or mapBlock operator: > {code} > test("C = A + B, identically partitioned") { > val inCoreA = dense((1, 2, 3), (3, 4, 5), (5, 6, 7)) > val A = drmParallelize(inCoreA, numPartitions = 2) > // Create B which would be identically partitioned to A. mapBlock() by > default will do the trick. > val B = A.mapBlock() { > case (keys, block) => > val bBlock = block.like() := { (r, c, v) => util.Random.nextDouble()} > keys -> bBlock > } > // Prevent repeated computation non-determinism > // flink problem is here... checkpoint is not doing what it should > .checkpoint() > val inCoreB = B.collect > printf("A=\n%s\n", inCoreA) > printf("B=\n%s\n", inCoreB) > val C = A + B > val inCoreC = C.collect > printf("C=\n%s\n", inCoreC) > // Actual > val inCoreCControl = inCoreA + inCoreB > (inCoreC - inCoreCControl).norm should be < 1E-10 > } > {code} > The output shous clearly that the line: > {code} > val bBlock = block.like() := { (r, c, v) => util.Random.nextDouble()} > {code} > in the {{mapBlock}} closure is being calculated more than once. > Output: > {code} > A= > { > 0 => {0:1.0,1:2.0,2:3.0} > 1 => {0:3.0,1:4.0,2:5.0} > 2 => {0:5.0,1:6.0,2:7.0} > } > B= > { > 0 => {0:0.26203398262809574,1:0.22561543461472167,2:0.23229669514522655} > 1 => {0:0.1638068194515867,1:0.18751822418846575,2:0.20586366231381614} > 2 => {0:0.9279465706239354,1:0.2963513448240057,2:0.8866928923235948} > } > C= > { > 0 => {0:1.7883652623225594,1:2.6401297718606216,2:3.0023341959374195} > 1 => {0:3.641411452208408,1:4.941233165480053,2:5.381282338548803} > 2 => {0:5.707434148862531,1:6.022780876943659,2:7.149772825494352} > } > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)