To defeat unwanted use of unicode, paste into a program which does not support unicode, inspect for defects (and correct them, if you find any) and then copy from there.
That said, for this infinite continued fraction stuff, it seems like representing the range of potential values from the infinite expression should be a useful tactic for seeing where it's going. Thanks, -- Raul On Fri, Jul 19, 2019 at 10:41 AM Devon McCormick <[email protected]> wrote: > > Fellow Jedi - > > There's a New Scientist article about some people who open-sourced some > code to attempt to accomplish Ramanujan-like discoveries in the area of > continued fractions: > https://www.newscientist.com/article/2209213-computer-attempts-to-replicate-the-dream-like-maths-of-ramanujan/ > . > > Unfortunately it is paywalled, so I will fair-use a little here: > > *The theorems Ramanujan produced often involved continued fractions, which > express a number as the sum of infinitely nested fractions.* > > *To mimic this approach, Gal Raayoni at the Israel Institute of Technology > and his colleagues created the Ramanujan Machine > <http://arxiv.org/abs/1907.00205>. It has already come up with tens > of conjectures that use continued fractions to approximate π and e.* > > *One method the program uses to search for new conjectures is a “meet in > the middle” approach. This involves generating many mathematical > expressions, computing their value for a limited number of iterations and > eliminating the expressions that give inaccurate results.* > Anyway, the formula for *e* they show in the article renders into J this > way: > > calcRamalikeE=: 13 : '(+`%)/,x:(3+i.y),.->:i.y'"0 > calcRamalikeE > ([: +`%`:3 [: , [: x: (3 + i.) ,. [: - [: >: i.)"0 > calcRamalikeE 10 20 > 9864101r3628800 6613313319248080001r2432902008176640000 > >50j48":&.>calcRamalikeE 10 20 > 2.718281801146384479717813051146384479717813051146 > 2.718281828459045235339784490666415886146403434540 > > All fine and good but when I tried to replicate this from memory at home > tonight, I kept getting a "spelling error" on the "(+`%)" part. Eventually > I figured out that what I'm typing in is rendering in Unicode and is > failing a spelling test. I'm running J64 8.07, Library 8.07.26, and, as > always, under Emacs on Windows. > > I'm afraid it may just be an Emacs thing as I had saved the problematic > session as "raw-text" earlier but I'd be pleased to hear from anyone who > could replicate or explain this or, even better, make sure it never happens > to anyone else ever again. > > Thanks, > > Devon > > -- > > Devon McCormick, CFA > > Quantitative Consultant > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
