“…This simple solution approach was further developed by many investigators in subsequent years. Apart from the standard RW, in which both step size and move directions are fixed and preassigned, two main random walk types were derived, namely semi floating random walk (step size is fixed, though the move direction is not limited, [47,52]) and full floating random walk (step size is not preassigned and changes at each step, whereas the move direction is not limited, [8,42,47,52]). Moreover, a continuous random walk procedure, minimizing the solution error has been proposed [17] along with the self-adaptive, grid-free algorithm, with improved solution smoothness and its application to diffusion equations [20].…”