A couple of errors. u&.v y is not the same as vi u v y
I know some writers have written that it is, but it's not. u&.:v y is the same as vi u v y . u&.v y is the same as u&.:v"v y (which means you do the &.: thing on cells whose size is given by the monadic rank of v). Use b. _1 to see the obverse: > b. _1 < (< i. >) 3 2 2 2 is not even close to right. That is a fork, and produces (< 3 2 2 2) i. (> 3 2 2 2) which is near nonsense. i.&.:> is equivalent to <@:i.@:> so i.&.> 3 2 2 2 is equivalent to (<@:i.@:>)"> 3 2 2 2 (<@:i.@:>)"> 3 2 2 2 +-----+---+---+---+ |0 1 2|0 1|0 1|0 1| +-----+---+---+---+ Henry Rich > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Terrence Brannon > Sent: Tuesday, June 19, 2007 4:13 PM > To: [email protected] > Subject: [Jgeneral] 'age spec astig tear'=: i.&.>3 2 2 2 NB. > not clear onthis... help needed > > Ok, > 'a b c' =: 1 2 3 NB. multiple assignments. this is easy > NB. therefore 'age spec astig tear'=: > NB. is easy for me to understand > NB. but the expression i.&.>3 2 2 2 > NB. has me confused. > > I read up on &. and we are dealing with the monadic case... > so: > > u&.v y IS THE SAME AS vi u v y > > which basically means 3 verbs get applied in sequence to y > > so: > i.&.>y IS THE SAME AS vi i. > y > where vi is the obverse of > > > Is there a programmatic way to get the obverse? > I'm guessing it is < NB. box > And why is the obverse applied to 0-cells of y? > > > So I think it actually is not to hard to figure out what this > is doing from a > holistic standpoint, but > (< i. >) 3 2 2 2 > > is not returning the same thing as > (i.&.>)3 2 2 2 > > which means I am making a mistake somewhere... > > Help appreciated. > > ---------------------------------------------------------------------- > For information about J forums see > http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
