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https://issues.apache.org/jira/browse/FLINK-3919?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15307367#comment-15307367
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ASF GitHub Bot commented on FLINK-3919:
---------------------------------------
Github user chobeat commented on a diff in the pull request:
https://github.com/apache/flink/pull/1996#discussion_r65134910
--- Diff:
flink-libraries/flink-ml/src/main/scala/org/apache/flink/ml/math/distributed/DistributedRowMatrix.scala
---
@@ -0,0 +1,182 @@
+/*
+ * 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.flink.ml.math.distributed
+
+import java.lang
+
+import breeze.linalg.{CSCMatrix => BreezeSparseMatrix, Matrix =>
BreezeMatrix, Vector => BreezeVector}
+import org.apache.flink.api.common.functions.RichGroupReduceFunction
+import org.apache.flink.api.common.typeinfo.TypeInformation
+import org.apache.flink.api.scala._
+import org.apache.flink.ml.math.{Matrix => FlinkMatrix, _}
+import org.apache.flink.util.Collector
+import org.apache.flink.ml.math.Breeze._
+import scala.collection.JavaConversions._
+
+/**
+ * Distributed row-major matrix representation.
+ * @param numRowsOpt If None, will be calculated from the DataSet.
+ * @param numColsOpt If None, will be calculated from the DataSet.
+ */
+class DistributedRowMatrix(data: DataSet[IndexedRow],
+ numRowsOpt: Option[Int] = None,
+ numColsOpt: Option[Int] = None)
+ extends DistributedMatrix {
+
+ lazy val getNumRows: Int = numRowsOpt match {
+ case Some(rows) => rows
+ case None => data.count().toInt
+ }
+
+ lazy val getNumCols: Int = numColsOpt match {
+ case Some(cols) => cols
+ case None => calcCols
+ }
+
+ val getRowData = data
+
+ private def calcCols: Int =
+ data.first(1).collect().headOption match {
+ case Some(vector) => vector.values.size
+ case None => 0
+ }
+
+ /**
+ * Collects the data in the form of a sequence of coordinates
associated with their values.
+ * @return
+ */
+ def toCOO: Seq[(Int, Int, Double)] = {
+
+ val localRows = data.collect()
+
+ for (IndexedRow(rowIndex, vector) <- localRows;
+ (columnIndex, value) <- vector) yield (rowIndex, columnIndex,
value)
+ }
+
+ /**
+ * Collects the data in the form of a SparseMatrix
+ * @return
+ */
+ def toLocalSparseMatrix: SparseMatrix = {
+ val localMatrix =
+ SparseMatrix.fromCOO(this.getNumRows, this.getNumCols, this.toCOO)
+ require(localMatrix.numRows == this.getNumRows)
+ require(localMatrix.numCols == this.getNumCols)
+ localMatrix
+ }
+
+ //TODO: convert to dense representation on the distributed matrix and
collect it afterward
+ def toLocalDenseMatrix: DenseMatrix =
this.toLocalSparseMatrix.toDenseMatrix
+
+ /**
+ * Apply a high-order function to couple of rows
+ * @param fun
+ * @param other
+ * @return
+ */
+ def byRowOperation(fun: (Vector, Vector) => Vector,
+ other: DistributedRowMatrix): DistributedRowMatrix = {
+ val otherData = other.getRowData
+ require(this.getNumCols == other.getNumCols)
+ require(this.getNumRows == other.getNumRows)
+
+
+ val result = this.data
+ .fullOuterJoin(otherData)
+ .where("rowIndex")
+ .equalTo("rowIndex")(
+ (left: IndexedRow, right: IndexedRow) => {
+ val row1 = Option(left).getOrElse(IndexedRow(
+ right.rowIndex,
+ SparseVector.fromCOO(right.values.size, List((0,
0.0)))))
+ val row2 = Option(right).getOrElse(IndexedRow(
+ left.rowIndex,
+ SparseVector.fromCOO(left.values.size, List((0,
0.0)))))
+
+ IndexedRow(row1.rowIndex, fun(row1.values, row2.values))
+ }
+ )
+ new DistributedRowMatrix(result, numRowsOpt, numColsOpt)
+ }
+
+ /**
+ * Add the matrix to another matrix.
+ * @param other
+ * @return
+ */
+ def sum(other: DistributedRowMatrix): DistributedRowMatrix = {
+ val sumFunction: (Vector, Vector) => Vector = (x: Vector, y: Vector) =>
+ (x.asBreeze + y.asBreeze).fromBreeze
+ this.byRowOperation(sumFunction, other)
+ }
+
+ /**
+ * Subtracts another matrix.
+ * @param other
+ * @return
+ */
+ def subtract(other: DistributedRowMatrix): DistributedRowMatrix = {
+ val subFunction: (Vector, Vector) => Vector = (x: Vector, y: Vector) =>
+ (x.asBreeze - y.asBreeze).fromBreeze
+ this.byRowOperation(subFunction, other)
+ }
+}
+
+object DistributedRowMatrix {
+
+ type MatrixRowIndex = Int
+
+ /**
+ * Builds a DistributedRowMatrix from a dataset in COO
+ * @param isSorted If false, sorts the row to properly build the matrix
representation.
+ * If already sorted, set this parameter to true to
skip sorting.
+ * @return
+ */
+ def fromCOO(data: DataSet[(Int, Int, Double)],
+ numRows: Int,
+ numCols: Int,
+ isSorted: Boolean = false): DistributedRowMatrix = {
+ val vectorData: DataSet[(Int, SparseVector)] = data
+ .groupBy(0)
+ .reduceGroup(sparseRow => {
+ require(sparseRow.nonEmpty)
+ val sortedRow =
+ if (isSorted) {
+ sparseRow.toList
+ } else {
+ sparseRow.toList.sortBy(row => row._2)
+ }
+ val (indices, values) = sortedRow.map(x => (x._2, x._3)).unzip
+ (sortedRow.head._1,
+ SparseVector(numCols, indices.toArray, values.toArray))
+ })
+
+ val zippedData = vectorData.map(x => IndexedRow(x._1.toInt, x._2))
+
+ new DistributedRowMatrix(zippedData, Some(numRows), Some(numCols))
+ }
+}
+
+case class IndexedRow(rowIndex: Int, values: Vector)
+ extends Ordered[IndexedRow] {
--- End diff --
I thought it was the most elegant and generic way to sort a list of
IndexedRow. If it's not the suggested way in Flink's codebase, I can remove it.
> Distributed Linear Algebra: row-based matrix
> --------------------------------------------
>
> Key: FLINK-3919
> URL: https://issues.apache.org/jira/browse/FLINK-3919
> Project: Flink
> Issue Type: New Feature
> Components: Machine Learning Library
> Reporter: Simone Robutti
> Assignee: Simone Robutti
>
> Distributed matrix implementation as a DataSet of IndexedRow and related
> operations
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