If this discussion is based on the briefly mentioned "f1 =: #.&1 _1 _2&>", that is admittedly a hack: it says so on that page. I've already changed the page to use the polynomial version.
Of greater concern is that once I update this page with what I've proposed, the lower section of the "Newton's Method" page is not so easily remedied as that demonstrates using the method with extended precision arguments to calculate the square root of 2 to arbitrary precision. I've always liked that example and would like to be able to retain that ability. On Sat, Jan 16, 2021 at 2:45 PM Hauke Rehr <[email protected]> wrote: > In this case, there is no well-defined fixed point, > no way of talking about “the” fixed point. > Any nonboxed value is a fixed point. > > What about “taking the derivative of ": ?” > All strings are fixed points. > > The question raised here is “what is > meant to be?” > Sure you can define it so that it wants to do what > it actually does. But I always thought of it as > unboxing, with the quirk that it doesn’t reject > unboxed values but works like no-op ] instead. > As a convenience. > > As always, YMMV > > Am 16.01.21 um 20:35 schrieb Justin Paston-Cooper: > > The fixed point of a function is a well-defined concept. > > > > On Sat, 16 Jan 2021 at 22:21, Hauke Rehr <[email protected]> wrote: > >> > >> There’s no sane way of talking about a “derivative of >” > >> > >> You said it shouldn’t concern itself with functions > >> meant for dealing with boxed arguments, which > is an > >> example of. If you’re not willing to state your numeric > >> function in terms of functions dealing with numeric > >> arguments only, you should be blamed. > >> > >> There is ]. > >> This is not by design meant for boxed-only arguments. > >> > >>> 3 works only as a convenience. Semantically, it’s crap. > >> I think it should be undefined behaviour officially. > >> Open to be changed to produce an error without notice. > >> > >> Don’t misunderstand me: I like using &.> and the like. > >> But I think it’s working against intended semantics > >> and always consider using > on unboxed arguments a hack. > >> > >> Am 16.01.21 um 20:12 schrieb Raul Miller: > >>> >3 > >>> 3 > >>> > >> > >> -- > >> ---------------------- > >> mail written using NEO > >> neo-layout.org > >> > >> ---------------------------------------------------------------------- > >> For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > > -- > ---------------------- > mail written using NEO > neo-layout.org > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > -- Devon McCormick, CFA Quantitative Consultant ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
