We improve recently introduced consensus-based optimization method, proposed
in [R. Pinnau, C. Totzeck, O. Tse and S. Martin, Math. Models Methods Appl. Sci.,
27(01):183{204, 2017], which is a gradient-free optimization method for general nonconvex
functions. We rst replace the isotropic geometric Brownian motion by the
component-wise one, thus removing the dimensionality dependence of the drift rate,
making the method more competitive for high dimensional optimization problems.
Secondly, we utilize the random mini-batch ideas to reduce the computational cost of
calculating the weighted average which the individual particles tend to relax toward.
For its mean- eld limit{a nonlinear Fokker-Planck equation{we prove, in both time
continuous and semi-discrete settings, that the convergence of the method, which
is exponential in time, is guaranteed with parameter constraints independent of the
dimensionality. We also conduct numerical tests to high dimensional problems to
check the success rate of the method.