If you have that line inside a function, then the variables will appear in the workspace of the function and you would have to assign them as outputs of the function to return them to the calling workspace. For example
function [x, y, n] = run_pc
v = rand(10); c = rand(20); b = rand(1,10);
[x, y, n] = pc(v, c, b);
end
and then
[x, y, n] = run_pc;
