You might want to look at Lab: Mapped Files Database 2007/12/5, Nick Kostirya <[EMAIL PROTECTED]>: > > Hi Everyone, > > Looking at the j, here's what I'm thinking of: "Why not make the > database like kdb on j ?" > > We need the special database, not the universal one. Or are there any > reefs ? Maybe k was optimized for this way of usage ? > > Besides, it's hard to change lines to columns. The analysis of > multivariates is simple, and when the base contains notes, it's > difficult to switch over. > > Maybe I need to present the data some other way ? > > Say, we have a chart with the quantity of apples people have (fields: > id_person and apples), and a chart that shows how many apples each > friend gives to them (id_person, id_friend,apples). We have to find > out how many apples everyone is going to have after friends share their > apples with these people. > > If one imagines 'in a matrix way', the friends-chart turns into a > matrix with 1 and 0 values. Next, the matrix is multiplied to vector > (how many apples each friend gives to each one). > > In a word, it's simple. However, there's a question: is there any > optimization for such actions ? I'm afraid, this matrix will gobble > all the memory . > Or should I still think 'in a matrix way', not 'with notes'? If I > think 'notes', I'll have to go thru the first table, and then to look > for the notes in the next table and calculate again. > > Which way is better and less resource-intensive ? > > Regards, Nick. > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm >
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