function current = bsc
% bsc Return the midpoint of binary search bracket [PHYS210-bs]
   global Bs_low Bs_high Bs_tol Bs_progress;
   if ~ bsinitialized
      warning('Search not initialized.  Use bsnew(low, high)');
      return;
   end
   current = 0.5 * (Bs_low(end) + Bs_high(end));
end
