  We investigate the application of the density-matrix renormalization group
(DMRG) algorithm to a one-dimensional harmonic oscillator chain and compare the
results with exact solutions, aiming to improve the algorithm efficiency. It
has been demonstrated that the algorithm can give quite accurate results if the
procedure is proper organized, for example, by using the optimized bases. The
errors of calculated ground state energy and the energy gap between the ground
state and the first excited state are analyzed, which are found to be
critically dependent upon the size of the system or the energy level structure
of the studied system and the number of states targeted during the DMRG
procedure.
