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Sajjad Bey commented on SPARK-11057: ------------------------------------ I have been trying to use correlation on a matrix with many columns. @NarineK menthioned R like correlation. I wish we had something like what [pandas](http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.corr.html) offers. It handles missing data automatically. Take a look [here](http://stackoverflow.com/questions/31619578/numpy-corrcoef-compute-correlation-matrix-while-ignoring-missing-data). Even the [corr()](http://spark.apache.org/docs/latest/api/python/pyspark.mllib.html#pyspark.mllib.stat.Statistics) function from MLlib can not handle missing data. These features are really missing from SparkSQL: - Apply correlation on all columns and return a matrix - Handle missing data automatically like how [pandas ](http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.corr.html)does > SQL: corr and cov for many columns > ---------------------------------- > > Key: SPARK-11057 > URL: https://issues.apache.org/jira/browse/SPARK-11057 > Project: Spark > Issue Type: New Feature > Components: SQL > Reporter: Narine Kokhlikyan > > Hi there, > As we know R has the option to calculate the correlation and covariance for > all columns of a dataframe or between columns of two dataframes. > If we look at apache math package we can see that, they have that too. > http://commons.apache.org/proper/commons-math/apidocs/org/apache/commons/math3/stat/correlation/PearsonsCorrelation.html#computeCorrelationMatrix%28org.apache.commons.math3.linear.RealMatrix%29 > In case we have as input only one DataFrame: > ------------------------------------------------------ > for correlation: > cor[i,j] = cor[j,i] > and for the main diagonal we can have 1s. > --------------------- > for covariance: > cov[i,j] = cov[j,i] > and for main diagonal: we can compute the variance for that specific column: > See: > http://commons.apache.org/proper/commons-math/apidocs/org/apache/commons/math3/stat/correlation/Covariance.html#computeCovarianceMatrix%28org.apache.commons.math3.linear.RealMatrix%29 > Let me know what do you think. > I'm working on this and will make a pull request soon. > Thanks, > Narine -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org