  We construct a four-dimensional version of the equation of state (EoS) model
NEOS, NEOS-4D, as a function of the temperature and chemical potentials of
baryon, electric charge, and strangeness for the hot and dense QCD matter
created in relativistic nuclear collisions. This EoS enables multiple conserved
charge current evolution in a relativistic fluid. Input from Lattice QCD
simulations and a hadron resonance gas model is considered for constructing the
equation of state. We investigate its applicability to the relativistic
hydrodynamic description of nuclear collisions and present a method for
efficient numerical implementation.
