Calculation of noise distribution in mesoscopic dynamics models for phase separation of multicomponent complex fluids

We present a simple method for the numerical calculation of the noise distribution in multicomponent functional Langevin models. The topic is of considerable importance, in view of the increased interest in the application of mesoscopic dynamics simulation models to phase separation of complex fluids in polymer and surfactant industries. We show that simple computational methods can be derived for a few (non)linear cases. The analysis contains three distinct steps: (I) factorization of the diffusion operator, (2) generation of auxiliary random fields and (3) Cholesky decomposition of the mobility operators.