  Multi-particle collision dynamics is an appealing numerical technique aiming
at simulating fluids at the mesoscopic scale. It considers molecular details in
a coarse-grained fashion and reproduces hydrodynamic phenomena. Here, the
implementation of multi-particle collision dynamics for isotropic fluids is
analysed under the so-called Andersen-thermostatted scheme, a particular
algorithm for systems in the canonical ensemble. This method gives rise to
hydrodynamic fluctuations that spontaneously relax towards equilibrium. This
relaxation process can be described by a linearized theory and used to
calculate transport coefficients of the system. The extension of the algorithm
for nematic liquid crystals is also considered. It is shown that thermal
fluctuations in the average molecular orientation can be described by an
extended linearized scheme. Flow fluctuations induce orientation fluctuations.
However, orientational changes produce observable effects on velocity
correlation functions only when simulation parameters exceed their values from
those used in previous applications of the method. Otherwise, the flow can be
considered to be independent of the orientation field.
