You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: VBA_getU.m
    path of file: ./repos/PsPM/src/ext/VBA
    
    the code of the file until where you have to start completion: function uu = VBA_getU(u,options,dim,flag)
% reshape micro-resolution driving input u
% function uu = VBA_getU(u,options,dim,flag)
% IN:
%   - u: macro-/micro- resolution input
%   - options: the options structure (see VBA_check.m)
%   - dim: the dim structure (see VBA_check.m)
%   - flag: gives the transformation direction (from micro- to macro- or
%   back...)
% OUT:
%   - uu: reshaped micro-resolution driving input

    
function uu = VBA_getU(u,options,dim,flag)
% reshape micro-resolution driving input u
% function uu = VBA_getU(u,options,dim,flag)
% IN:
%   - u: macro-/micro- resolution input
%   - options: the options structure (see VBA_check.m)
%   - dim: the dim structure (see VBA_check.m)
%   - flag: gives the transformation direction (from micro- to macro- or
%   back...)
% OUT:
%   - uu: reshaped micro-resolution driving input

if options.microU && ~isequal(options.decim,1)
    switch flag
        case '2macro'
            u0 = u;
            nut = dim.u*options.decim;
            uu = zeros(nut,dim.n_t);
            for t=1:dim.n_t
                uu(:,t) = vec(u0(:,(t-1)*options.decim+1:t*options.decim));
            end