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: fibonacciS2Grid_find_region.m
    path of file: ./repos/mtex/geometry/@fibonacciS2Grid/private
    
    the code of the file until where you have to start completion: function varargout = fibonacciS2Grid_find_region(fibgrid, v, epsilon)
% return incex of all points in a ep
    
function 
test_id_cell = cell(s, 1);
grid_id_cell = cell(s, 1);
dist_cell = cell(s, 1);
nn = zeros(s, 1);

% if theta_big is true we first determine all grid points that are suitable
% w.r.t. their theta angle and throw away the ones that differ too much
% w.r.t. the rho angle 
% if theta_big is false we do it vice versa
% it should be faster due to the reduced average size of the relevant
% indice that remains after the first step
% TODO: this should also be depend