% Indexing
a = 100:-1:1
found = find(isprime(a))

b = a(found) % found is a list of integers representing indices of a

% An example of permutation, but 'permute' or 'randperm' might be faster
arun = zeros(1,5);
arun([2 1 4 3 5]) = 10:15; % 10 => arun(2), 11 => arun(1), ...

% Logical indexing; return values of 'a' for which 'logicals' is true.
% Don't confuse this with indexing an array with another array!  Logical
% indexing must be done with an array of data-type 'logical' and must have the
% same length as the array being indexed.
logicals = isprime(a)
c = a(logicals)

c(12) = 33;
b(b == c)
intersect(b,c) % Equivalent, but sorted in order


% Logical operators
evens = (mod(a,2) == 0)

a(logicals & evens)
a(logicals | evens)

% Short-circuit operator example
% x = (denom ~= 0) && (numer / denom > 6)


% Outer products: in CNS, these are especially useful for creating stimuli
% that are identical for most time steps in a simulation
row_in = [ones(1,20) 5*ones(1,20) 3*ones(1,20)];
col_in = [1/60:1/60:1]';
in = col_in * row_in;

[y,x] = meshgrid(1:60,1:60);
mesh(x,y,in)


% Concatenation is just plain neat and a good trick to have handy
x = [1 2 3; 4 5 6; 7 8 9; 10 11 12];
y = [1 1 1; 2 2 2; 3 3 3;  4  4  4];
t = [0 0 1; 1 0 0; 0 0 1;  1  1  0];

points = [x(:) y(:) t(:)]; % Ready to be output as a table

mat3d = reshape(points, [4 3 3]); % multidimensional array