If it is not too much effort I am interested in a copy as well. No worries I am German and can cross read. Actually I am more on the kdb side but I am interested in J also.
Thanks, Kim Von meinem iPhone gesendet > Am 15.10.2020 um 17:25 schrieb Martin Kreuzer <[email protected]>: > > Hello Hauke - > > That sounds very interesting -- I too would be glad to receive a copy (if > it's not asking too much - you could use PM in that case); > btw, I'm a fellow citizen (former Math teacher, long retired = a.D., besides > other occupations) losely following forum discussions (not much of a > contributor lately due to personal reasons). > > -M > > At 2020-10-15 14:20, you wrote: >> Hello Stefan, I guess by your name and email adress that youâre from >> austria so you could read and understand German. I took lecture notes last >> year in a Numerics course here at the university of Jena and implemented >> nearly all of the algorithms using J, with coloured J lines interspersed >> with the notes. (typeset with LaTeX and the minted package) I used explicit >> code in some places but most of it is tacit and thus without for. style >> loops. But of course there need to be ^: style loops in many places. EDIT: I >> just did a /for\. search and it turned out I didnât use it at all >> For example, the line for the newton representation of the lagrange >> polynomial reads Newton =: 1 : â[: +/ (nbase pmul u divdiff)\â NB. pmul >> aus Beispiel 1.40 where 1.40 is a clickable back-reference. All the other >> names have been defined in the current section. Up to that point there are >> no explicit definitions at all. If youâre interested, Iâll ask if I may >> send you the pdf file (I guess it will be okay) in case youâre interested. >> cheers, Hauke Am 15.10.20 um 15:50 schrieb Stefan Baumann: > Dear all. > >> Recently I stumbled upon the Newton polynomial and took it as a practice to >> > implement it without using loops, but failed. I first didn't get a grab on >> > how to create the matrix used in > >> https://en.wikipedia.org/wiki/Newton_polynomial#Main_idea, and eventually > >> came up with code following > >> https://en.wikipedia.org/wiki/Newton_polynomial#Application: > > NB. Newton >> polynomial > > np=: 4 : 0 > > a=. {. y > > for_i. }.>:i.#x do. > > y=. (2 >> (-~)/\ y) % i ({:-{.)\ x NB. Divided differences > > a=. a, {. y NB. >> Coefficients are the topmost entries > > end. > > NB. Convert the summands >> aáµ¢(x-xâ) > (x-xáµ¢ââ) of the >> polynomial > > NNB. from multiplier-and-roots to coefficients form and add >> them up > > +/@,:/ p."1 (;/a) ,. (<''), }:<\ x > > ) > > x=: _3r2 _3r4 0 3r4 >> 3r2 > > y=: 3&o. x > > load'plot' > > load'stats' > > plot (];(x np y)&p.) >> steps _1.5 1.5 30 > > I also tried replacing the loop with fold F:. but >> again was not able to do > so. Anyone out there who can enlighten me? > > >> Many thanks. Stefan. > >> ---------------------------------------------------------------------- > >> 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 >> </x-flowed> > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
