在 Sat, 25 Apr 2009 23:40:03 +0800，dsimcha <[email protected]> 写道:
== Quote from dsimcha ([email protected])'s article
== Quote from Simen Kjaeraas ([email protected])'s article
> dsimcha wrote:
> > RangeExtra version 10^-20 is officially out. It consists of a
small and
> > hopefully growing number of ranges that didn't make it into the new
> > Phobos
> > that I've gotten working reasonably well and I feel eventually
belong in
> > Phobos.
> >
> > Docs / What's there:
> > http://cis.jhu.edu/~dsimcha/rangeextra.html
> >
> > Code:
> >
http://dsource.org/projects/scrapple/browser/trunk/rangeextra/rangeextra.d
> >
> > License:
> > Dual licensed, Phobos license or BSD (Tango style).
> I had hoped reindex would give me access to true 'random' access
ranges, but it
seems this does not work:
> auto b = reindex!( "uniform( 0, this.length )" )( [0,1,2,3,4].dup );
> :p
On the other hand, I really like the idea of a with-replacement random
sampling
primitive. This sounds like it belongs in RandomCover. Maybe Andrei
can extend
RandomCover (which already samples w/o replacement) to include a
replacement
parameter. RandomCover w/ replacement == false would do what it does
now. If
replacement == true, it would be an infinite range that samples with
replacement.
Here's a first attempt: I took Andrei's RandomCover, fixed bug 2865
(This version
of RandomCover passes basic statistical tests for uniformity of the
distribution
over the permutation space), and added a template overload to allow
sampling with
replacement. It's under the Phobos license to make it as easy as
possible to add
back to Phobos. I'll file an enhancement request.
http://dsource.org/projects/scrapple/browser/trunk/rangeextra/randomcover.d
Looking forward to it!
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