Thanks for the correction!. I forgot that (fg)y means y f gy . I was thinking about the differences in the trees and wasn't paying attention to the math.
Maybe that is what woke me up so early and so restless... Linda -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Alex Giannakopoulos Sent: Monday, October 15, 2012 2:21 AM To: [email protected] Subject: Re: [Jprogramming] another example of 'under' On 15 October 2012 06:37, Linda Alvord <[email protected]> wrote: > Sometimes you get the double of the reciprocal and other times the > reciprocal of the double. > Erm, not quite, Linda. You will see that the hook (%+:) will always return 0.5, no matter what the input. Remember, (fg)y means y f gy when you are using a hook. In other words the first verb of the hook is a dyad, so in our example represents division, not inversion. To give an example, I would "translate" this hook mentally thus: "The y argument divided by its double" (hence always 0.5) Similarly (+!) would mean the argument added to its factorial, while (!>:) would mean choose y from y+1 (! is dyadic here) so the answer will always be y+1 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
