> --Original Message--On Behalf Of bill lam > for the inverted data, > > I want to sort the s with the first three columns, the > primary key is the first, secondary key the second etc. I do > this by sorting successively (sorting in j is stable), > > There should be other better method, eg, can it be done using > permutation vectors? > Have you checked Roger's Inverted Tables on the wiki? There's a section there on grading & sorting. http://www.jsoftware.com/jwiki/Essays/Inverted_Table
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