[SPARK-1434] [MLLIB] change labelParser from anonymous function to trait
This is a patch to address @mateiz 's comment in https://github.com/apache/spark/pull/245 MLUtils#loadLibSVMData uses an anonymous function for the label parser. Java users won't like it. So I make a trait for LabelParser and provide two implementations: binary and multiclass. Author: Xiangrui Meng <meng@databricks.com> Closes #345 from mengxr/label-parser and squashes the following commits: ac44409 [Xiangrui Meng] use singleton objects for label parsers 3b1a7c6 [Xiangrui Meng] add tests for label parsers c2e571c [Xiangrui Meng] rename LabelParser.apply to LabelParser.parse use extends for singleton 11c94e0 [Xiangrui Meng] add return types 7f8eb36 [Xiangrui Meng] change labelParser from annoymous function to trait
This commit is contained in:
parent
ce8ec54561
commit
b9e0c937df
|
@ -0,0 +1,49 @@
|
|||
/*
|
||||
* 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.spark.mllib.util
|
||||
|
||||
/** Trait for label parsers. */
|
||||
trait LabelParser extends Serializable {
|
||||
/** Parses a string label into a double label. */
|
||||
def parse(labelString: String): Double
|
||||
}
|
||||
|
||||
/**
|
||||
* Label parser for binary labels, which outputs 1.0 (positive) if the value is greater than 0.5,
|
||||
* or 0.0 (negative) otherwise. So it works with +1/-1 labeling and +1/0 labeling.
|
||||
*/
|
||||
object BinaryLabelParser extends LabelParser {
|
||||
/** Gets the default instance of BinaryLabelParser. */
|
||||
def getInstance(): LabelParser = this
|
||||
|
||||
/**
|
||||
* Parses the input label into positive (1.0) if the value is greater than 0.5,
|
||||
* or negative (0.0) otherwise.
|
||||
*/
|
||||
override def parse(labelString: String): Double = if (labelString.toDouble > 0.5) 1.0 else 0.0
|
||||
}
|
||||
|
||||
/**
|
||||
* Label parser for multiclass labels, which converts the input label to double.
|
||||
*/
|
||||
object MulticlassLabelParser extends LabelParser {
|
||||
/** Gets the default instance of MulticlassLabelParser. */
|
||||
def getInstance(): LabelParser = this
|
||||
|
||||
override def parse(labelString: String): Double = labelString.toDouble
|
||||
}
|
|
@ -38,17 +38,6 @@ object MLUtils {
|
|||
eps
|
||||
}
|
||||
|
||||
/**
|
||||
* Multiclass label parser, which parses a string into double.
|
||||
*/
|
||||
val multiclassLabelParser: String => Double = _.toDouble
|
||||
|
||||
/**
|
||||
* Binary label parser, which outputs 1.0 (positive) if the value is greater than 0.5,
|
||||
* or 0.0 (negative) otherwise.
|
||||
*/
|
||||
val binaryLabelParser: String => Double = label => if (label.toDouble > 0.5) 1.0 else 0.0
|
||||
|
||||
/**
|
||||
* Loads labeled data in the LIBSVM format into an RDD[LabeledPoint].
|
||||
* The LIBSVM format is a text-based format used by LIBSVM and LIBLINEAR.
|
||||
|
@ -69,7 +58,7 @@ object MLUtils {
|
|||
def loadLibSVMData(
|
||||
sc: SparkContext,
|
||||
path: String,
|
||||
labelParser: String => Double,
|
||||
labelParser: LabelParser,
|
||||
numFeatures: Int,
|
||||
minSplits: Int): RDD[LabeledPoint] = {
|
||||
val parsed = sc.textFile(path, minSplits)
|
||||
|
@ -89,7 +78,7 @@ object MLUtils {
|
|||
}.reduce(math.max)
|
||||
}
|
||||
parsed.map { items =>
|
||||
val label = labelParser(items.head)
|
||||
val label = labelParser.parse(items.head)
|
||||
val (indices, values) = items.tail.map { item =>
|
||||
val indexAndValue = item.split(':')
|
||||
val index = indexAndValue(0).toInt - 1
|
||||
|
@ -107,14 +96,7 @@ object MLUtils {
|
|||
* with number of features determined automatically and the default number of partitions.
|
||||
*/
|
||||
def loadLibSVMData(sc: SparkContext, path: String): RDD[LabeledPoint] =
|
||||
loadLibSVMData(sc, path, binaryLabelParser, -1, sc.defaultMinSplits)
|
||||
|
||||
/**
|
||||
* Loads binary labeled data in the LIBSVM format into an RDD[LabeledPoint],
|
||||
* with number of features specified explicitly and the default number of partitions.
|
||||
*/
|
||||
def loadLibSVMData(sc: SparkContext, path: String, numFeatures: Int): RDD[LabeledPoint] =
|
||||
loadLibSVMData(sc, path, binaryLabelParser, numFeatures, sc.defaultMinSplits)
|
||||
loadLibSVMData(sc, path, BinaryLabelParser, -1, sc.defaultMinSplits)
|
||||
|
||||
/**
|
||||
* Loads labeled data in the LIBSVM format into an RDD[LabeledPoint],
|
||||
|
@ -124,7 +106,7 @@ object MLUtils {
|
|||
def loadLibSVMData(
|
||||
sc: SparkContext,
|
||||
path: String,
|
||||
labelParser: String => Double): RDD[LabeledPoint] =
|
||||
labelParser: LabelParser): RDD[LabeledPoint] =
|
||||
loadLibSVMData(sc, path, labelParser, -1, sc.defaultMinSplits)
|
||||
|
||||
/**
|
||||
|
@ -135,7 +117,7 @@ object MLUtils {
|
|||
def loadLibSVMData(
|
||||
sc: SparkContext,
|
||||
path: String,
|
||||
labelParser: String => Double,
|
||||
labelParser: LabelParser,
|
||||
numFeatures: Int): RDD[LabeledPoint] =
|
||||
loadLibSVMData(sc, path, labelParser, numFeatures, sc.defaultMinSplits)
|
||||
|
||||
|
|
|
@ -0,0 +1,41 @@
|
|||
/*
|
||||
* 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.spark.mllib.util
|
||||
|
||||
import org.scalatest.FunSuite
|
||||
|
||||
class LabelParsersSuite extends FunSuite {
|
||||
test("binary label parser") {
|
||||
for (parser <- Seq(BinaryLabelParser, BinaryLabelParser.getInstance())) {
|
||||
assert(parser.parse("+1") === 1.0)
|
||||
assert(parser.parse("1") === 1.0)
|
||||
assert(parser.parse("0") === 0.0)
|
||||
assert(parser.parse("-1") === 0.0)
|
||||
}
|
||||
}
|
||||
|
||||
test("multiclass label parser") {
|
||||
for (parser <- Seq(MulticlassLabelParser, MulticlassLabelParser.getInstance())) {
|
||||
assert(parser.parse("0") == 0.0)
|
||||
assert(parser.parse("+1") === 1.0)
|
||||
assert(parser.parse("1") === 1.0)
|
||||
assert(parser.parse("2") === 2.0)
|
||||
assert(parser.parse("3") === 3.0)
|
||||
}
|
||||
}
|
||||
}
|
|
@ -80,7 +80,7 @@ class MLUtilsSuite extends FunSuite with LocalSparkContext {
|
|||
Files.write(lines, file, Charsets.US_ASCII)
|
||||
val path = tempDir.toURI.toString
|
||||
|
||||
val pointsWithNumFeatures = MLUtils.loadLibSVMData(sc, path, 6).collect()
|
||||
val pointsWithNumFeatures = MLUtils.loadLibSVMData(sc, path, BinaryLabelParser, 6).collect()
|
||||
val pointsWithoutNumFeatures = MLUtils.loadLibSVMData(sc, path).collect()
|
||||
|
||||
for (points <- Seq(pointsWithNumFeatures, pointsWithoutNumFeatures)) {
|
||||
|
@ -93,7 +93,7 @@ class MLUtilsSuite extends FunSuite with LocalSparkContext {
|
|||
assert(points(2).features === Vectors.sparse(6, Seq((1, 4.0), (3, 5.0), (5, 6.0))))
|
||||
}
|
||||
|
||||
val multiclassPoints = MLUtils.loadLibSVMData(sc, path, MLUtils.multiclassLabelParser).collect()
|
||||
val multiclassPoints = MLUtils.loadLibSVMData(sc, path, MulticlassLabelParser).collect()
|
||||
assert(multiclassPoints.length === 3)
|
||||
assert(multiclassPoints(0).label === 1.0)
|
||||
assert(multiclassPoints(1).label === -1.0)
|
||||
|
|
Loading…
Reference in a new issue