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: packing_on_the_sphere.m
    path of file: ./repos/lrslibrary/libs/manopt/examples
    
    the code of the file until where you have to start completion: function [X maxdot] = packing_on_the_sphere(d, n, epsilon, X0)
% Return a set of points spread out on the sphere.
%
% function [X maxdot] = packing_on_the_sphere(d, n, epsilon, X0)
%
% Using optimization on the oblique manifold, that is, the product of
% spheres, this function returns a set of n points with unit norm in R^d in
% the form of a matrix X of size nxd, such that the points are spread out
% on the sphere. Ideally, we would minimize the maximum inner product
% between any two points X(i, :) and X(j, :), i~=j, but that is a nonsmooth
% cost function. Instead, we re
    
function with caching system used: the store
    % structure we receive as input is tied to the input point X. Everytime
    % this cost function is called at this point X, we will receive the
    % same store structure back. We may modify the store structure inside
    % the function and return it: the changes will be remembered for next
    % time.
    function [f store] = cost(X, store)
        if ~isfield(store, 'ready')
            XXt = X*X';
            % Shift the exponentials by the maximum value to reduce
            % numerical trouble due to possible overflows.
            s = max(max(triu(XXt, 1)));
            expXXt = exp((XXt-s)/epsilon);
            % Zero out the diagonal
            expXXt(1:(n+1):end