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From: Joshua Carmichael on 14 Mar 2010 20:16
chariya peterson <chariya(a)kong.gsfc.nasa.gov> wrote in message <35D363FD.B308740C(a)kong.gsfc.nasa.gov>...
> This is a multi-part message in MIME format.
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> <HTML>
> Hi,
> <BR>Sorry for duplicate post.  The original post was under the wrong
> subject.
>
> <P>I just posted a question about cell structure.  But my news server
> is kind of slow.  I found one solution before the original question
> appears.  Let me restate the
> <BR>problem:
>
> <P>Given a finite set, anom, (represented by a cell array).  lds is
> a function that
> <BR>generates the power set of anon.  So the output of lds (hyp) should
> also be a cell
> <BR>array, each of whose cell is a cell (with no subcell).
>
> <P>Here is a solution:
>
> <P>function hyp=lds(anom)
> <BR>x=size(anom);
> <BR>hyp={};
> <BR>for i = 1:x(2)
> <BR>   hyp2={anom{i}};
> <BR>   for j = 1:2^(i-1)-1
> <BR>      n=size(hyp{j});
> <BR>      p={};  z={};
> <BR>      for k =1:n(2)
> <BR>         z{1}=deal(hyp{j}{k})
> <BR>         p=[p,z]
> <BR>      end
> <BR>      y = {[p {deal(anom{i}{:})}]}
> <BR>      hyp2=[hyp2, y]
> <BR>   end
> <BR>   hyp=[hyp, hyp2]
> <BR>end
> <BR>hyp=[hyp, {{''}}]
> <BR>return
> <BR> 
> <BR> 
> <BR>There must be a better way to do this.  Is there ?
> <BR>chariya
> <BR> 
> <BR> 
> <BR> </HTML>
>
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> fn: Chariya Peterson
> n: Peterson;Chariya
> org: Computer Sciences Corp
> email;internet: chariya(a)kong.gsfc.nasa.gov
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>

Did anyone ever respond to this thread with an answer? I have been searching for a Matlab function to compute power sets, and this is the one entry I could find. I used lds provided by the author and it worked perfectly; the solution is elegant, and I don't see an obvious improvement.
From: Jos (10584) on 15 Mar 2010 02:53
"Joshua Carmichael" <joshuadc(a)u.washington.edu> wrote in message <hnju85$1o$1(a)fred.mathworks.com>...
> chariya peterson <chariya(a)kong.gsfc.nasa.gov> wrote in message <35D363FD.B308740C(a)kong.gsfc.nasa.gov>...

> Did anyone ever respond to this thread with an answer? I have been searching for a Matlab function to compute power sets, and this is the one entry I could find. I used lds provided by the author and it worked perfectly; the solution is elegant, and I don't see an obvious improvement.

Take a look at my NCHOOSE function available on the File Exchange, which is fast and vectorized. NCHOOSE almost returns the powerset, that is, you have to add the empty set explicitly

S = {'a', 1:4 , {'c1',123}}
PowerSet = nchoose(S) ;
PowerSet(end+1) = [] % add empty set

http://www.mathworks.com/matlabcentral/fileexchange/20011

hth
Jos
From: Joshua Carmichael on 18 Mar 2010 23:03
"Jos (10584) " <#10584(a)fileexchange.com> wrote in message <hnklge$nvg$1(a)fred.mathworks.com>...
> "Joshua Carmichael" <joshuadc(a)u.washington.edu> wrote in message <hnju85$1o$1(a)fred.mathworks.com>...
> > chariya peterson <chariya(a)kong.gsfc.nasa.gov> wrote in message <35D363FD.B308740C(a)kong.gsfc.nasa.gov>...
>
> > Did anyone ever respond to this thread with an answer? I have been searching for a Matlab function to compute power sets, and this is the one entry I could find. I used lds provided by the author and it worked perfectly; the solution is elegant, and I don't see an obvious improvement.
>
> Take a look at my NCHOOSE function available on the File Exchange, which is fast and vectorized. NCHOOSE almost returns the powerset, that is, you have to add the empty set explicitly
>
> S = {'a', 1:4 , {'c1',123}}
> PowerSet = nchoose(S) ;
> PowerSet(end+1) = [] % add empty set
>
> http://www.mathworks.com/matlabcentral/fileexchange/20011
>
> hth
> Jos

Thanks, I will download it. I don't need the empty set anyways :-)
josh
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