  Simulations of gas-solid mixtures are used in many scientific and industrial
applications. Two-Fluid Smoothed Particle Hydrodynamics (TFSPH) is an approach
when gas and solids are simulated with different sets of particles interacting
via drag force. Several methods are developed for computing drag force between
gas and solid grains for TFSPH. Computationally challenging are simulations of
gas-dust mixtures with intense intephase interaction, when velocity relaxation
time $t_{\rm stop}$ is much smaller than dynamical time of the problem. In
explicit schemes the time step $\tau$ must be less than $t_{\rm stop}$, that
leads to high computational costs. Moreover, it is known that for stiff
problems both grid-based and particle methods may require unaffordably detailed
resolution to capture the asymptotical bahaiviour of the solution. To address
this problem we developed fast and robust method for computing stiff and mild
drag force in gas solid-mixtures based on the ideas of Particle-in-Cell
approach. In the paper we compare the results of new and previously developed
methods on test problems
