You return it as an output argument.
Like the MATLAB documentation clearly states, the best practice is to pass arguments:
So your function could be something like:
function [ct,A] = critPT( ... )
...
A = ...
ct = ...
...
end
and then call it:
[NewCT,newA] = critPT(...)
Note: the fact that you do not "see" the variable A in the base workspace is the whole point of functions: they should have independent workspaces, so that what happens inside any one function does not affect any other workspace. That is the point.
