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How do I save each iteration of a loop into a matrix?

Asked by SammyJoe on 18 Oct 2019
Latest activity Commented on by per isakson
on 18 Oct 2019
This is my code; the problem is when I use a loop for circular shifts, I need each iteration to be saved into a matrix so I can concantenate it with two other matrices and take out duplicates
% This script will calculate the number of possible arrangements for a
% necklace given a certain number of beads assuming circular shifts and
% flips are the same
%Create a vector with the beads where a number is assigned to each color
v=[1 1 2 2 3 4];
% 1=red
% 2=blue
% 3=yellow
% 4=green
% Determine total number of beads and all possible permutations
n=numel(v);
p=perms(v);
% Take into account colors with >1 beads
p2=unique(perms(v),'rows');
% Generate flips of all permutations
f=fliplr(p2);
% Generate circular shifts for all permutations
for i=0:n
c=circshift(p, [0, i]);
end
% Combine the three matrices into one and remove duplicate rows
combined=[p2;f;c];
final=unique(combined,'rows');
configurations=size(final,1);
fprintf('The number of possible configurations is %d\n',configurations)

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1 Answer

Answer by per isakson
on 18 Oct 2019
Edited by per isakson
on 18 Oct 2019

Replace
for i=0:n
c=circshift(p, [0, i]);
end
by
c = nans(n,1);
for i=0:n
c(i)=circshift(p, [0, i]);
end

  2 Comments

This gives this error:
Undefined function or variable 'nans'.
Error in configurebeads1 (line 23)
c = nans(n,1);
My fault, the name of the function is nan
Then there is another problem. The Matlab arrays are one-based.
Thus
c = nan(n+1,1);
for i=0:n
c(i+1)=circshift(p, [0, i]);
end

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