How to split a nxn matrix into n vectors
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Hi at all, I want to split a nxn matrix in n vectors:
M= [1 2 3 ; 4 5 6 ; 7 8 9];
in
m1 = [1 2 3];
m2 = [4 5 6];
m3 = [7 8 9];
I know that m1=M(1,:);
m2=M(2,:) ... ...
m(n)=M(n,:)
but if the matrix is very large how can I resolve? Thanks a lot
Max
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Più risposte (3)
Jan
il 16 Nov 2012
Using a list of variable like "m1, m2, ..." is a really bad idea and it increases the complexity of programs without any advantage. Andrei's suggestion to use a cell array is much better. See
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Andrei Bobrov
il 16 Nov 2012
Modificato: Andrei Bobrov
il 16 Nov 2012
eg
M= [1 2 3 ; 4 5 6 ; 7 8 9];
m = num2cell(M,2);
out = polyder(m{1:2}); % for your version out = polyder(m1,m2);
Jan
il 16 Nov 2012
"Struct"? Structs have field names, but I do not see any field names here. Do you mean "cell array"?
I think that Andrei has guessed already, what you are trying to do. But in general in is more efficient, when you explain exactly, what you are trying to do.
Matt Fig
il 16 Nov 2012
Jan is correct. Doing this is a bad idea. If you need to use the POLYDER function on each row of a large array, there are several ways to do it without making many variables.
M = randi(4,6,4);
N = num2cell(M,2);
PD = cellfun(@polyder,N,'Un',0)
Now PD{1} is the POLYDER of M(1,:), PD{2} is the POLYDER of M(2,:), etc.
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