That, of course, depends on how attractive the invitees are. (with apologies for drifting off-topic) ------------------------------------------------------------------------ |\/| Randy A MacDonald | APL: If you can say it, it's done.. (ram) |/\| [EMAIL PROTECTED] | |\ | | The only real problem with APL is that BSc(Math) UNBF'83 | it is "still ahead of its time." Sapere Aude | - Morten Kromberg Natural Born APL'er | Demo website: http://156.34.82.188/ -----------------------------------------------------(INTP)----{ gnat }-
----- Original Message ----- From: "Roger Hui" <[EMAIL PROTECTED]> To: "Programming forum" <programming@jsoftware.com> Sent: Saturday, February 03, 2007 4:32 PM Subject: Re: [Jprogramming] Collatz Problem again > Even if a program is going to be run just once or > a problem is already solved there is satisfaction > in doing it well for oneself. The pursuit of Truth > and Beauty makes life worth living. Better than > watching the Super Bowl, for instance. > > > > ----- Original Message ----- > From: Devon McCormick <[EMAIL PROTECTED]> > Date: Saturday, February 3, 2007 11:22 am > Subject: Re: [Jprogramming] Collatz Problem again > > > June - > > > > how many times do you plan to solve the problem or do you plan to > > extend the search? > > > > I'm asking because I just wrote "collatz" myself for the > > projectEuler math > > challenge. My version, which I wrote in less than 5 minutes, took > > about1350 seconds to complete for the first million integers. > > Obviously,Roger's version is far faster. > > > > However, I may never run this code again. > > > > I looked at one of the discussion groups on the math challenge site > > and, typically, much of the talk was about shaving seconds off an > > implementation of code to solve one of the problems. > > > > I still fail to grasp the economics of spending hours of one's own, > > irreplaceable time to save seconds of processing time, especially > > for one-shot solutions and especially since I can do other things > > in the 1300 seconds I "waste" by not running faster code. > > > > Apologies to long-time readers of this forum for this re-iteration > > of my standard rant, number one on the list, but it continues to be > > relevant. > > > > Just to point out the benefits of coding quickly and > > inefficiently, in the > > few days since I got interested in this math challenge, I've > > gotten my > > ranking up to around 380 out of 2089, so I've passed about 1700 > > people. > > Not to brag: I owe it to J and a little of it to advance peeks at > > some of the problems people have asked about on the forum. > > > > I probably should really be embarrassed that I'm gaining on people > > in a race where most of them are crawling, wearing boxes on their > > heads and dragging chains. > > > > So, I'm unwilling to spend more than a few minutes to improve on a > > solution, especially one that Roger wrote. However, his essay on the > > solution is worthwhile, especially for the notion of caching > > results, as > > this has general applicability and may be a time-saver in the future. > > > > Good luck, > > > > Devon > > > > On 2/3/07, June Kim <[EMAIL PROTECTED]> wrote: > > > > > > Have a look at this problem: > > > > > > http://www.programming- > > challenges.com/pg.php?page=downloadproblem&probid=110101&format=html> > > > In short, you need to calculate the maximum cycle length in a > > given range. > > > > > > Roger wrote an essay which is related to this problem. > > > http://www.jsoftware.com/jwiki/Essays/Collatz_Conjecture > > > > > > Suppose we want to calculate the maximum cycle length of collatz > > > sequences for 1, ..., 1e6. > > > > > > It would be defined, using Roger's definition, as >./ cn 1e6 > > > > > > It currently takes around 40 secs on the computer I'm using. > > Could you > > > improve its efficiency? > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
