Kuang Chen created SPARK-23091: ---------------------------------- Summary: Incorrect unit test for approxQuantile Key: SPARK-23091 URL: https://issues.apache.org/jira/browse/SPARK-23091 Project: Spark Issue Type: Improvement Components: ML Affects Versions: 2.2.1 Reporter: Kuang Chen
Currently, test for `approxQuantile` (quantile estimation algorithm) checks whether estimated quantile is within +- 2*`relativeError` from the true quantile. See the code below: [https://github.com/apache/spark/blob/master/sql/core/src/test/scala/org/apache/spark/sql/DataFrameStatSuite.scala#L157] However, based on the original paper by Greenwald and Khanna, the estimated quantile is guaranteed to be within +- `relativeError` from the true quantile. Using the double "tolerance" is misleading and incorrect, and we should fix it. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org