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From: Jos (10584) on 26 Feb 2010 08:27
Rune Allnor <allnor(a)tele.ntnu.no> wrote in message <af2e7889-0795-4d3e-b9cc-650a01628d0e(a)d27g2000yqf.googlegroups.com>...

* snip

> If you want this for real, the most efficient way to
> swap columns is this:
>
> B=A;
> B(:,1)=A(:,2);
> B(:,2)=A(:,1);


or swap in a single statement

B = A ; % work on a copy
B(:,[1 2]) = B(:,[2 1]) % swap using right-hand indexing
B(:,[2 1]) = B(:,[1 2]) % swap (back) using left hand indexing

hth
Jos
From: Matt Dunham on 1 Mar 2010 13:11
"BHARATH " <bhushabhusha(a)gmail.com> wrote in message <hm2h9c$76q$1(a)fred.mathworks.com>...
> hi
>
> i have a matrix , A.
> i will multiply with permutation matrix for interchange of columns.
>
> i have to know which columns have been changed by their position value.
> i.e, if A's column position are 1 2 3 4 for orginal one
>
> and for permutated one as 3 4 1 2...
>
> please help me in indexing....

Try using the find function on the permutation matrix.
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