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Topic: permutations
Replies: 1   Last Post: Aug 14, 2014 9:50 AM

 Messages: [ Previous | Next ]
 patrick Posts: 15 Registered: 1/25/05
permutations
Posted: Aug 13, 2014 1:41 PM

I wrote a function which gives you all possibles sums of the entities of a vector. This is done for two summands only. However, I would need to do this for 3, 4, 5, n summands of a vector. Maybe it is possible to change the code (below!) accordingly???

Any help on that is highly appreciated!

A minimal example for 2 summands is given here:

A=rand(20,1)
function [val1]=sum_perm_poss(A)

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

function [val1]=sum_perm_poss(vector)
%

%%
vector(vector==0)=[NaN];
x=1;

len_vec=numel(vector);
len_vec_red=len_vec-1;
siz1=factorial(len_vec)/(factorial(2)*factorial(len_vec-2));

for ii=1:len_vec_red
a=1;
for i=1:len_vec-x
sum_permi(i,ii)=vector(i,1)+vector(i+x,1);
val2(i,ii)=a;
val3(i,ii)=x;
a=a+1;
end

x=x+1;

end

val1(:,1)=sum_permi(:);
val1(:,2)=val2(:);
val1(:,3)=val3(:);
val1(val1(:,1:3)==0)=[];
val1=reshape(val1,[siz1,3]);

return

Date Subject Author
8/13/14 patrick
8/14/14 patrick