disp('new num2str')
tic
ii = 0;
while ii < 1000
  ii = ii + 1;
  x = num2str(2);
end
toc
disp('old num2str')
tic
ii = 0;
while ii < 1000
  ii = ii + 1;
  x = num2str_old(2);
end
toc
