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Timothy Hunter edited comment on SPARK-19208 at 2/14/17 9:24 PM: ----------------------------------------------------------------- Thanks for the clarification [~mlnick]. I was a bit unclear in my previous comment. What I meant by catalyst rules is supporting the case in which the user would naturally request multiple summaries: {code} val summaryDF = df.select(VectorSummary.min("features"), VectorSummary.variance("features")) {code} and have a simple rule that rewrites this logical tree to use a single UDAF under the hood: {code} val tmpDF = df.select(VectorSummary.summary("features", "min", "variance")) val df2 = tmpDF.select(col("vector_summary(features).min").as("min(features)"), col("vector_summary(features).variance").as("variance(features)") {code} Of course this is more advanced, and we should probably start with: - a UDAF that follows some builder pattern such as VectorSummarizer.metrics("min", "max").summary("features") - some simple wrappers that (inefficiently) compute independently their statistics: {{VectorSummarizer.min("feature")}} is a shortcut for: {code} VectorSummarizer.metrics("min").summary("features").getCol("min") {code} etc. We can always optimize this use case later using rewrite rules. What do you think? was (Author: timhunter): Thanks for the clarification [~mlnick]. I was a bit unclear in my previous comment. What I meant by catalyst rules is supporting the case in which the user would naturally request multiple summaries: {code} val summaryDF = df.select(VectorSummary.min("features"), VectorSummary.variance("features")) {code} and have a simple rule that rewrites this logical tree to use a single UDAF under the hood: {code} val tmpDF = df.select(VectorSummary.summary("features", "min", "variance")) val df2 = tmpDF.select(col("VectorSummary(features).min").as("min(features)"), col("VectorSummary(features).variance").as("variance(features)") {code} Of course this is more advanced, and we should probably start with: - a UDAF that follows some builder pattern such as VectorSummarizer.metrics("min", "max").summary("features") - some simple wrappers that (inefficiently) compute independently their statistics: {{VectorSummarizer.min("feature")}} is a shortcut for: {code} VectorSummarizer.metrics("min").summary("features").getCol("min") {code} etc. We can always optimize this use case later using rewrite rules. What do you think? > MultivariateOnlineSummarizer performance optimization > ----------------------------------------------------- > > Key: SPARK-19208 > URL: https://issues.apache.org/jira/browse/SPARK-19208 > Project: Spark > Issue Type: Improvement > Components: ML > Reporter: zhengruifeng > Attachments: Tests.pdf, WechatIMG2621.jpeg > > > Now, {{MaxAbsScaler}} and {{MinMaxScaler}} are using > {{MultivariateOnlineSummarizer}} to compute the min/max. > However {{MultivariateOnlineSummarizer}} will also compute extra unused > statistics. It slows down the task, moreover it is more prone to cause OOM. > For example: > env : --driver-memory 4G --executor-memory 1G --num-executors 4 > data: > [http://www.csie.ntu.edu.tw/~cjlin/libsvmtools/datasets/binary.html#kdd2010%20(bridge%20to%20algebra)] > 748401 instances, and 29,890,095 features > {{MaxAbsScaler.fit}} fails because of OOM > {{MultivariateOnlineSummarizer}} maintains 8 arrays: > {code} > private var currMean: Array[Double] = _ > private var currM2n: Array[Double] = _ > private var currM2: Array[Double] = _ > private var currL1: Array[Double] = _ > private var totalCnt: Long = 0 > private var totalWeightSum: Double = 0.0 > private var weightSquareSum: Double = 0.0 > private var weightSum: Array[Double] = _ > private var nnz: Array[Long] = _ > private var currMax: Array[Double] = _ > private var currMin: Array[Double] = _ > {code} > For {{MaxAbsScaler}}, only 1 array is needed (max of abs value) > For {{MinMaxScaler}}, only 3 arrays are needed (max, min, nnz) > After modication in the pr, the above example run successfully. -- This message was sent by Atlassian JIRA (v6.3.15#6346) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org