Define permutation map on {1,2,3}

I want to define a function which .

How could I do this?

Answer 1

[Voss]

% you can index into a vector:
S_vec = [2 3 1];

% or you can define an anonymous function:
S_func = @(x)mod(x,3)+1;

% they work the same:
S_vec(1)

ans = 2

S_vec(2)

ans = 3

S_vec(3)

ans = 1

S_func(1)

ans = 2

S_func(2)

ans = 3

S_func(3)

ans = 1

% and both work for vector inputs:
S_vec([1 2 3])

ans = 1×3

2 3 1

S_func([1 2 3])

ans = 1×3

2 3 1