  We propose an extrapolation technique that allows accuracy improvement of the
discrete dipole approximation computations. The performance of this technique
was studied empirically based on extensive simulations for 5 test cases using
many different discretizations. The quality of the extrapolation improves with
refining discretization reaching extraordinary performance especially for
cubically shaped particles. A two order of magnitude decrease of error was
demonstrated. We also propose estimates of the extrapolation error, which were
proven to be reliable. Finally we propose a simple method to directly separate
shape and discretization errors and illustrated this for one test case.
