@ and @: have different meanings, in the general case. For common specific cases where they do not have different meanings, it's reasonable for special code to be used to speed up @
Specifically: u@v where u's ranks do not exceed v's ranks and where v's result shape is depends strictly on its argument shape (or where v's result shape is constant) probably warrants special code.l Thanks, -- Raul On Fri, Sep 29, 2017 at 9:53 AM, Erling Hellenäs <[email protected]> wrote: > Hi all! > > From these simple examples it does not seem to be any difference in time and > space requirements between the [:+] syntax and the +@:] syntax. Not even if > we insert more brackets. > > ts'(i.v) ([:+[:+[:+[:+]) i.v=.1000000' > > 0.00936323 1.67808e7 > > ts'(i.v) (+@:+@:+@:+@:]) i.v=.1000000' > > 0.00935086 1.67808e7 > > ts'(i.v) (+@:(+@:(+@:(+@:])))) i.v=.1000000' > > 0.00925313 1.67811e7 > > > As we can see using @ instead of @: has a heavy penalty in both time and > space requirements. > > > ts'(i.v) (+@+@+@+@]) i.v=.1000000' > > 0.341589 1.69553e8 > > > Cheers, > > Erling > > > On 2017-09-29 05:31, Henry Rich wrote: >> >> It seems a bit much to ask Raul to track down a recent email thread. >> >> No, @: does not create a namespace. Only explicit entities have a >> namespace. >> >> Henry Rich >> >> On 9/28/2017 11:19 PM, Erling Hellenäs wrote: >>> >>> On 2017-09-29 04:59, Raul Miller wrote: >>>> >>>> I do not know of any definition of "namespace" such that @: creates a >>>> namespace. >>>> >>>> Why do you think that @: creates a namespace? >>>> >>>> Thanks, >>>> >>> As I said there was a discussion about this in a long thread recently. >>> Maybe you can find it? This is from what I remember of this thread, it's not >>> from my own investigations. >>> >>> /Erling >>> >>> ---------------------------------------------------------------------- >>> For information about J forums see http://www.jsoftware.com/forums.htm >> >> >> >> --- >> This email has been checked for viruses by AVG. >> http://www.avg.com >> >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm > > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
