MATLAB: What does permute actually produce

MATLABpermute

Trying some calculations earlier, I have realised permute does not do what I thought it did. To clarify I did this
    % code
test = rand(4,4,4,4) + rand(4,4,4,4)*1i;
test2a = zeros(4,4,4,4); test2b = zeros(4,4,4,4); 
for a = 1:4
    for b = 1:4
        for c = 1:4
            for d = 1:4
test2a(a,b,c,d) = test(a,b,d,c);
test2b(a,b,c,d) = test(b,a,c,d); 
            end
        end
    end
end
test3a = permute(test,[1,2,4,3]);
test3b = permute(test,[2,1,3,4]);
m1=max(test2a(:)-test3a(:))
m2=max(test2b(:)-test3b(:))
test2a = zeros(4,4,4,4); test2b = zeros(4,4,4,4); 
for a = 1:4
    for b = 1:4
        for c = 1:4
            for d = 1:4
test2a(a,b,c,d) = test(d,b,a,c);
test2b(a,b,c,d) = test(c,a,b,d); 
            end
        end
    end
end
test3a = permute(test,[4,2,1,3]); 
test3b = permute(test,[3,1,2,4]);
m3=max(test2a(:)-test3a(:))
m4=max(test2b(:)-test3b(:))
m1 =
     0
m2 =
     0
m3 =
   0.9525 + 0.5183i
m4 =
   0.9293 - 0.7266i
clearly the first is the same but the latter is different. Is there some way to create the second variables (of form test2(a,b,c,d) == test(d,b,a,c) which involve two permutations ) just using permute on test?

Best Answer

Isn't it
var2 = permute(var1,[3 2 4 1]);
?
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