So, you start with $10,000 (=100*$100) but end up with $2,025 (=45*$45), how?
On Mon, Jul 10, 2017 at 3:59 PM, Raul Miller <rauldmil...@gmail.com> wrote: > I don't really understand what you mean by "mean expectations" - could > you describe the intent there? > > That said, here's how far I've gotten in implementing this concept: > > tick=: (0 >. <:) + i.@# +/@:(=/)~ +/@:* ?@# # > (mean,stddev)"1 tick^:(i.10)]100#100 > 100 0 > 100 0.932034 > 100 1.41421 > 100 1.91749 > 100 2.07437 > 100 2.34844 > 100 2.48633 > 100 2.71546 > 100 2.97803 > 100 3.26289 > > (Also, for animation in J, there's actually a lot of options... > basically though you set up a paint event which calls into your > rendering code and then trigger updates from systimer.) > > Thanks, > > -- > Raul > > On Mon, Jul 10, 2017 at 3:43 PM, Xiao-Yong Jin <jinxiaoy...@gmail.com> > wrote: > > I thought this is a good lunch break exercise. > > > > http://www.decisionsciencenews.com/2017/06/19/counterintuitive- > problem-everyone-room-keeps-giving-dollars-random-others- > youll-never-guess-happens-next/ > > > > Quote: “Imagine a room full of 100 people with 100 dollars each. With > every tick of the clock, every person with money gives a dollar to one > randomly chosen other person. After some time progresses, how will the > money be distributed?” > > > > And I came up with this simulation. (45 people with 45 dollars each, > same as on the webpage.) > > > > /:~@(-&1`]@.(=&0)"0 (#/.~@] + ~.@]{[)`(~.@])`[} >&0 # (?@#~@#@]`]`[} > ]I.@:=i.@#)^:_@?@#~@#)^:5000 #~45 > > > > And I really like to see the mean expectations and the standard > deviation of the mean, I ended up doing this. (Make sure the J sentence is > one long line if you want to try it out.) > > > > ((],.[:(+/%#*<:@#)&.:*: -"1)+/%#)}.(/:~@(-&1`]@.(=&0)"0 (#/.~@] + > ~.@]{[)`(~.@])`[} >&0 # (?@#~@#@]`]`[} ]I.@:=i.@#)^:_@?@#~@#)^:10000)^:(<65) > #~45 > > 0.984375 0.124984 > > 2.01562 0.170335 > > 3.0625 0.180765 > > 4.15625 0.230616 > > 5.21875 0.248476 > > 6.1875 0.306894 > > 7.35938 0.332862 > > 8.64062 0.362809 > > 9.84375 0.380723 > > 10.9688 0.383805 > > 12.125 0.407944 > > 13.6406 0.423964 > > 15.0625 0.457453 > > 16.5312 0.462893 > > 18.1875 0.480717 > > 19.7031 0.464877 > > 21.1562 0.475709 > > 22.7031 0.483702 > > 24.4062 0.516935 > > 26.4062 0.5768 > > 28.1094 0.604266 > > 29.8281 0.617838 > > 31.875 0.61942 > > 33.9375 0.603345 > > 35.7812 0.642211 > > 37.9844 0.647987 > > 40.6562 0.731321 > > 43 0.739342 > > 45.3906 0.723616 > > 48.0469 0.7613 > > 51.6094 0.823639 > > 54.7656 0.873934 > > 57.1406 0.815544 > > 60 0.866598 > > 63.8594 0.898319 > > 68.75 0.918018 > > 73.5781 1.00736 > > 78.3281 1.08128 > > 84.9688 1.25534 > > 93.4688 1.29731 > > 104.578 1.73274 > > 114.922 2.07574 > > 131.938 2.7357 > > 159.359 4.40899 > > 204.766 7.24239 > > > > So, how do I make a fancy animation (like the one in the webpage I > linked in the beginning of this message) with J? > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- > 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
