Thx for a very good explanation. I am not used to these kind of notation but it does make sense when you explain it.
Now I hope someone can explain how to do a) and b) 2009/3/27 Dan Bron <[email protected]> > Björn wrote: > > c) I am curious of what this number 1r10800p1 is all about. > > That's conversion to arc minutes in radians, I think. An arc minute is > 1%60 of a degree or (1%60) * pi%180 radians. The notation 1r10800p1 > is just a shorthand (atomic, single-word) way of expressing (1%60) * > pi%180 . > > Briefly: > > (1%60) * pi%180 > pi % (60 * 180) > pi % 10800 > 1p1 % 10800 NB. 1p1 means pi > 1p1 * (1 % 10800) NB. Re-express to take advantage of J's > constant hierarchy > (1 % 10800) * 1p1 > 1r10800 * 1p1 > 1r10800p1 > > See how expressive (effort-saving) a good notation can be? > > '3.0' 8!:2 (,. 100 * 1 - %/)(,.&#&>~;:&.>) '1r10800p1' ; > '(1%60) * 1p1%180' > 1 9 89 > 9 16 44 > > A savings of almost 50% in characters, and 90% in words. > > It gets even better when you consider the single-word version removes the > requirement for parenthesis and/or assignment, since the value is used more > than once, and always leftmost in an expression. > > -Dan > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm -- Björn Helgason, Verkfræðingur Fugl&Fiskur ehf, Þerneyjarsundi 23, Hraunborgum Po Box 127,801 Selfoss , t-póst: [email protected] gsm: +3546985532 Landslags og skrúðgarðagerð, gröfuþjónusta http://groups.google.com/group/J-Programming Tæknikunnátta höndlar hið flókna, sköpunargáfa er meistari einfaldleikans góður kennari getur stigið á tær án þess að glansinn fari af skónum /|_ .-----------------------------------. ,' .\ / | Með léttri lund verður | ,--' _,' | Dagurinn í dag | / / | Enn betri en gærdagurinn | ( -. | `-----------------------------------' | ) | (\_ _/) (`-. '--.) (='.'=) ♖♘♗♕♔♙ `. )----' (")_(") ☃☠ ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
