Nothing about futures here either, but shouldn't the sum of the list be kept aside it somehow? You're recalculating the sum of the selected values many many times here. <div class="gmail_quote">On Wed, Jul 28, 2010 at 21:44, Matthias Felleisen <<a href="mailto:matthias@ccs.neu.edu">matthias@ccs.neu.edu</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"> (Nothing about futures. But may I recommend a nice and simple 'optimization': (cond [(= 1 (length values)) ...] adds quite some complexity to a recursive function over a list. I'd use (empty? (rest values)) instead. Also, I assume that you will protect your function with a contract or a main function. -- Matthias) <div><div></div><div class="h5"> On Jul 28, 2010, at 4:35 PM, Joe Snikeris wrote: > All, > > Please see: <a href="http://pastie.org/1064484" target="_blank">http://pastie.org/1064484</a> > > Apparently, spawning futures recursively is a bad idea. This problem > seems like it should be easily parallelizable. What am I doing wrong > here? > > Thanks, > Joe > _________________________________________________ > For list-related administrative tasks: > <a href="http://lists.racket-lang.org/listinfo/users" target="_blank">http://lists.racket-lang.org/listinfo/users</a> _________________________________________________ For list-related administrative tasks: <a href="http://lists.racket-lang.org/listinfo/users" target="_blank">http://lists.racket-lang.org/listinfo/users</a> </div></div></blockquote></div>