Or, more generally, you need to iterate on an item where k,s, and t are functions of that item, as is the stopping condition.
A boxed list is one example of this kind of approach but it need not be the only example. If nothing else, since k,s, and t are all numeric, I'm not sure I see the need for boxing. For example, we might defer the computation of s until later, this lets us get k from the length of the list of values that t takes on. I think Roger already posted an implementation for this approach. Thanks, -- Raul On Sun, Dec 22, 2013 at 11:18 AM, Henry Rich <[email protected]> wrote: > I can't figure out a pleasing way to do this. You need 4 things: k,s,y,t. > 3 of these change. So, you need to join them as a boxed list and then > iterate, but you can't iterate until they stop changing, because the > iteration number always changes. t also changes. Yuck. > > Henry Rich > > > > On 12/22/2013 3:27 AM, km wrote: >> >> Thanks, Raul, for a cool solution. I'm still interested in tacitly >> terminating a series when its partial sums stop changing. --Kip >> >> Sent from my iPad >> >>> On Dec 22, 2013, at 12:34 AM, Raul Miller <[email protected]> wrote: >>> >>> ^ 2 >>> 7.38906 >>> (%!i.40) p. 2 >>> 7.38906 >>> (^ = (%!i.40)&p.) 0j1p1 >>> 1 >>> >>> I'd just use ^ >>> >>> -- >>> Raul >>> >>>> On Sat, Dec 21, 2013 at 5:43 PM, km <[email protected]> wrote: >>>> Verb exp below uses the series for monadic ^ to calculate ^ y . >>>> Can you remind me how to do exp tacitly? You may omit the "clean" >>>> part. >>>> Verb clean replaces tiny real numbers by 0 . >>>> >>>> clean =: (* *!.1e_14@|)"0&.+. >>>> >>>> exp =: 3 : 0 >>>> os =. 0 >>>> s =. 1 >>>> k =. 0 >>>> t =. 1 >>>> while. s ~: os do. >>>> os =. s >>>> k =. >: k >>>> t =. t * y % k >>>> s =. s + t >>>> end. >>>> clean s >>>> ) >>>> >>>> exp 1 >>>> 2.71828 >>>> >>>> ^1 >>>> 2.71828 >>>> >>>> exp 0j1p1 >>>> _1 >>>> >>>> ^ 0j1p1 >>>> _1j1.22465e_16 >>>> >>>> (^0j1p1) = exp 0j1p1 >>>> 1 >>>> >>>> VERSION NB. iPad >>>> 1.3 5 >>>> >>>> --Kip Murray >>>> >>>> Sent from my iPad >>>> >>>> ---------------------------------------------------------------------- >>>> 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 >> > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
