An Adaptive Euler--Maruyama Scheme for ...

We study the strong approximation of stochastic differential equations with discontinuous drift coefficients and (possibly) degenerate diffusion coefficients. To account for the discontinuity of the drift coefficient we construct an adaptive step sizing strategy for the explicit Euler--Maruyama scheme. As a result, we obtain a numerical method which has---up to logarithmic terms---strong convergence order $1/2$ with respect to the average computational cost.  We support our theoretical findings with several numerical examples.