Perhaps in a bit of a clumsy way I tried to report last Thursday that inserting a value in a large sparse array (changing an element from "zero" into something else) had become quite slow.
SIZE=:1000000000000000 A =: 1 $. SIZE i =: ?1000000 $ SIZE v =: 1+?1000000 $ 1000 6!:2 'A =: v i } A' NB. insert 1 million values 0.179232 6!:2 ' A =: (999) 12345678901234 } A' NB. one more value 99.8308 The time depends strongly (quadratically?) on the number of elements already in the array. This is J-903. In J-902 the same amend takes 220s. Apparently it is a J9 thing, because I had not noticed it earlier. I checked with j64-807 and it is only 0.24s. Usually I'm on Linux, but meanwhile I tried the same in Windows 10 with similar results. Perhaps I'm the only one with this issue, but I wonder whether this is this a glitch in the current J system that may be repaired -- or am I somehow doing something inappropriate and is there a much better solution? ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
