  The ENUF method, i.e., Ewald summation based on the Non-Uniform FFT technique
(NFFT), is implemented in Dissipative Particle Dynamics (DPD) simulation scheme
to fast and accurately calculate the electrostatic interactions at mesoscopic
level. In a simple model electrolyte system, the suitable ENUF-DPD parameters,
including the convergence parameter $\alpha$, the NFFT approximation parameter
$p$, and the cut-offs for real and reciprocal space contributions, are
carefully determined. With these optimized parameters, the ENUF-DPD method
shows excellent efficiency and scales as $\mathcal{O}(N\log N)$. The ENUF-DPD
method is further validated by investigating the effects of charge fraction of
polyelectrolyte, ionic strength and counterion valency of added salts on
polyelectrolyte conformations. The simulations in this paper, together with a
separately published work of dendrimer-membrane complexes, show that the
ENUF-DPD method is very robust and can be used to study charged complex systems
at mesoscopic level.
