CHOOSENK All choices of K elements taken from 1:N [X]=(N,K) The output X is a matrix of size (N!/(K!*(N-K)!),K) where each row contains a choice of K elements taken from 1:N without duplications. The rows of X are in lexically sorted order. To choose from the elements of an arbitrary vector V use V(CHOOSENK(LENGTH(V),K)).

- choosrnk CHOOSRNK All choices of K elements taken from 1:N with replacement. [X]=(N,K)
- minspane MINSPANE calculate minimum spanning tree using euclidean distance [p,s]=X

0001 function x=choosenk(n,k) 0002 %CHOOSENK All choices of K elements taken from 1:N [X]=(N,K) 0003 % The output X is a matrix of size (N!/(K!*(N-K)!),K) where each row 0004 % contains a choice of K elements taken from 1:N without duplications. 0005 % The rows of X are in lexically sorted order. 0006 % 0007 % To choose from the elements of an arbitrary vector V use 0008 % V(CHOOSENK(LENGTH(V),K)). 0009 0010 % CHOOSENK(N,K) is the same as the MATLAB5 function NCHOOSEK(1:N,K) but is 0011 % much faster for large N and most values of K. 0012 0013 % Copyright (c) 1998 Mike Brookes, mike.brookes@ic.ac.uk 0014 % Version: $Id: choosenk.m 713 2011-10-16 14:45:43Z dmb $ 0015 % 0016 % VOICEBOX is a MATLAB toolbox for speech processing. 0017 % Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html 0018 % 0019 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0020 % This program is free software; you can redistribute it and/or modify 0021 % it under the terms of the GNU General Public License as published by 0022 % the Free Software Foundation; either version 2 of the License, or 0023 % (at your option) any later version. 0024 % 0025 % This program is distributed in the hope that it will be useful, 0026 % but WITHOUT ANY WARRANTY; without even the implied warranty of 0027 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 0028 % GNU General Public License for more details. 0029 % 0030 % You can obtain a copy of the GNU General Public License from 0031 % http://www.gnu.org/copyleft/gpl.html or by writing to 0032 % Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA. 0033 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0034 0035 kk=min(k,n-k); 0036 if kk<2 0037 if kk<1 0038 if k==n 0039 x=1:n; 0040 else 0041 x=[]; 0042 end 0043 else 0044 if k==1 0045 x=(1:n)'; 0046 else 0047 x=1:n; 0048 x=reshape(x(ones(n-1,1),:),n,n-1); 0049 end 0050 end 0051 else 0052 n1=n+1; 0053 m=prod(n1-kk:n)/prod(1:kk); 0054 x=zeros(m,k); 0055 f=n1-k; 0056 x(1:f,k)=(k:n)'; 0057 for a=k-1:-1:1 0058 d=f; 0059 h=f; 0060 x(1:f,a)=a; 0061 for b=a+1:a+n-k 0062 d=d*(n1+a-b-k)/(n1-b); 0063 e=f+1; 0064 f=e+d-1; 0065 x(e:f,a)=b; 0066 x(e:f,a+1:k)=x(h-d+1:h,a+1:k); 0067 end 0068 end 0069 end

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