I think we should put in a list shuffler into the core.
Which should we use? The faster one?
Jay
On Thu, Nov 11, 2010 at 11:26 AM, Eli Barzilay e...@barzilay.org wrote:
5 minutes ago, Neil Toronto wrote:
Carl Eastlund wrote:
It's pick a random, uniform ordering, and then sort based on it.
I think we want the one recommended by the statisticians. :)
Robby
On Fri, Nov 12, 2010 at 2:36 PM, Jay McCarthy jay.mccar...@gmail.com wrote:
I think we should put in a list shuffler into the core.
Which should we use? The faster one?
Jay
On Thu, Nov 11, 2010 at 11:26 AM, Eli Barzilay
Any objections to `shuffle' in `racket/list'?
--
((lambda (x) (x x)) (lambda (x) (x x))) Eli Barzilay:
http://barzilay.org/ Maze is Life!
_
For list-related administrative tasks:
Not by me.
On Fri, Nov 12, 2010 at 2:25 PM, Eli Barzilay e...@barzilay.org wrote:
Any objections to `shuffle' in `racket/list'?
--
((lambda (x) (x x)) (lambda (x) (x x))) Eli Barzilay:
http://barzilay.org/ Maze is Life!
I find myself using this all the time; it seems it'd be handy to have built in.
(define (shuffled list)
(sort list #:key (lambda (_) (random)) #:cache-keys? #t))
Thanks.
_
For list-related administrative tasks:
Eric Hanchrow wrote:
I find myself using this all the time; it seems it'd be handy to have built in.
(define (shuffled list)
(sort list #:key (lambda (_) (random)) #:cache-keys? #t))
Is the distribution of shuffled lists uniform? That'd be hard to
analyze, since it would depend on the
On Thu, Nov 11, 2010 at 12:18 PM, Neil Toronto neil.toro...@gmail.com wrote:
Eric Hanchrow wrote:
I find myself using this all the time; it seems it'd be handy to have
built in.
(define (shuffled list)
(sort list #:key (lambda (_) (random)) #:cache-keys? #t))
Is the distribution of
I think that if random doesn't pick the same number twice you're
guaranteed to be independent of the sorting algorithm, at least.
Robby
On Thu, Nov 11, 2010 at 11:18 AM, Neil Toronto neil.toro...@gmail.com wrote:
Eric Hanchrow wrote:
I find myself using this all the time; it seems it'd be
On Thu, Nov 11, 2010 at 12:40 PM, Neil Toronto neil.toro...@gmail.com wrote:
I don't know. I know that the run through the list and swap with another
random element algorithms are usually non-uniform, and so are a lot of
other things that seem like they'd work. I wouldn't use something that
On Thu, Nov 11, 2010 at 11:40 AM, Carl Eastlund c...@ccs.neu.edu wrote:
On Thu, Nov 11, 2010 at 12:40 PM, Neil Toronto neil.toro...@gmail.com wrote:
I don't know. I know that the run through the list and swap with another
random element algorithms are usually non-uniform, and so are a lot of
5 minutes ago, Neil Toronto wrote:
Carl Eastlund wrote:
It's pick a random, uniform ordering, and then sort based on it.
The random keys are chosen per element and cached (hence
#:cache-keys? #t), not per comparison.
Spanking good point, my good man. I think you're right.
It's a very
When truly picking uniformally shuffled lists from a given list, see:
http://telefonica.net/web2/koot/natural-to-permutation.scm
and try
(require srfi/27) ; for random-integer
(require natural-to-permutation.scm)
(let*
((lst (build-list 1000 (lambda (k) (round (quotient k 10)
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