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https://issues.apache.org/jira/browse/MAHOUT-1583?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14039798#comment-14039798
]
ASF GitHub Bot commented on MAHOUT-1583:
----------------------------------------
Github user sscdotopen commented on a diff in the pull request:
https://github.com/apache/mahout/pull/20#discussion_r14049574
--- Diff:
spark/src/main/scala/org/apache/mahout/sparkbindings/blas/CbindAB.scala ---
@@ -0,0 +1,95 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.mahout.sparkbindings.blas
+
+import org.apache.log4j.Logger
+import scala.reflect.ClassTag
+import org.apache.mahout.sparkbindings.drm.DrmRddInput
+import org.apache.mahout.math._
+import scalabindings._
+import RLikeOps._
+import org.apache.mahout.math.drm.logical.OpCbind
+import org.apache.spark.SparkContext._
+
+/** Physical cbind */
+object CbindAB {
+
+ private val log = Logger.getLogger(CbindAB.getClass)
+
+ def cbindAB_nograph[K: ClassTag](op: OpCbind[K], srcA: DrmRddInput[K],
srcB: DrmRddInput[K]): DrmRddInput[K] = {
+
+ val a = srcA.toDrmRdd()
+ val b = srcB.toDrmRdd()
+ val n = op.ncol
+ val n1 = op.A.ncol
+ val n2 = n - n1
+
+ // Check if A and B are identically partitioned AND keyed. if they
are, then just perform zip
+ // instead of join, and apply the op map-side. Otherwise, perform join
and apply the op
+ // reduce-side.
+ val rdd = if (op.isIdenticallyPartitioned(op.A)) {
+
+ log.debug("applying zipped cbind()")
+
+ a
+ .zip(b)
+ .map {
+ case ((keyA, vectorA), (keyB, vectorB)) =>
+ assert(keyA == keyB, "inputs are claimed identically
partitioned, but they are not identically keyed")
+
+ val dense = vectorA.isDense && vectorB.isDense
+ val vec: Vector = if (dense) new DenseVector(n) else new
SequentialAccessSparseVector(n)
--- End diff --
Wouldn't it be more performant to use a RandomAccessSparseVector for the
assign and change it into a SequentialAcessSparseVector later?
> cbind() operator for Scala DRMs
> -------------------------------
>
> Key: MAHOUT-1583
> URL: https://issues.apache.org/jira/browse/MAHOUT-1583
> Project: Mahout
> Issue Type: Task
> Reporter: Dmitriy Lyubimov
> Assignee: Dmitriy Lyubimov
> Fix For: 1.0
>
>
> Another R-like operator, cbind (stitching two matrices together). Seems to
> come up now and then.
> Just like with elementwise operations, and, perhaps some other, it will have
> two physical implementation paths, one is zip for identically distributed
> operators, and another one is full join in case they are not.
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