swap elements in a matrix

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Giannakis Stoukas
Giannakis Stoukas le 20 Mar 2015
Commenté : the cyclist le 10 Mai 2018
Hello i want to swap elements in a matrix.I want to do it to elements of the same row and to elements of differents rows. Please help.Thank you
  2 commentaires
Adam
Adam le 20 Mar 2015
An example would be useful, although the usual method for swapping elements is to use a temporary variable to store one while you copy the other over the top of it and then copy from the temporary variable into the 2nd location.
Giannakis Stoukas
Giannakis Stoukas le 20 Mar 2015
Modifié(e) : the cyclist le 20 Mar 2015
To be more specific i want to execute local search to a matrix like this one
A=[1 4 7 16 32 48 1;
1 5 6 23 1 0 0;
1 9 31 8 2 1 0;
1 11 19 66 1 0 0]
The the elements of the matrix are arcs(for example 9-31 is the arc between nodes 9 and 31),so i want to make enough exchanges to reduce the cost.I can do exchanges of the same row like the 9 with 31 and i will the 3 row 1 31 9 8 2 1 0 and the other rows as they were,and i can do exchanges of different rows like the node 9 with the node 11. Is there any command to swap,or i have to use temp variables?

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the cyclist
the cyclist le 20 Mar 2015
Modifié(e) : the cyclist le 10 Mai 2018
% A matrix:
A = magic(3);
% Swap the first and second elements of the first column:
A([1 2]) = A([2 1])
% Swap the first and second elements of the third column:
A([7 8]) = A([8 7])
% Swap the first and third elements of the first row:
A([1 7]) = A([7 1])
Note that I needed to take advantage of linear indexing.
  4 commentaires
YANAN ZHU
YANAN ZHU le 9 Mai 2018
A([1 7]) = A([7 1]) actually swap the first and third elements of the first row, not "Swap the first and second elements of the first row"
the cyclist
the cyclist le 10 Mai 2018
Oops, there were actually a couple confusing typos in my post. I have edited to correct them. Thanks for pointing that out.

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Plus de réponses (1)

Ahamed Tuani
Ahamed Tuani le 13 Nov 2017
Hi,
I have been looking into local search as well. Giannakis, I know its quite q while ago but have you figure out how to do it?
The cyclist and fellow members, I have a question..say the path is 1-31-9-2-10-1..I want to swap 9 and 2 so that the new path will be 1-31-2-9-10-1. How can I do this? Tried indexing (maybe a dumb way) i.e init_tour((1:2):(4):(3):6) to get the new tour but its not working. Any help will be greatly appreciated. Thanks.

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