%0 Journal Article %T An Implicit Euler Scheme with Non-uniform Time Discretization for Heat Equations with Multiplicative Noise %A Thoms Mueller-Gronbach %A Klaus Ritter %J Mathematics %D 2006 %I arXiv %X We present an algorithm for solving stochastic heat equations, whose key ingredient is a non-uniform time discretization of the driving Brownian motion $W$. For this algorithm we derive an error bound in terms of its number of evaluations of one-dimensional components of $W$. The rate of convergence depends on the spatial dimension of the heat equation and on the decay of the eigenfunctions of the covariance of $W$. According to known lower bounds, our algorithm is optimal, up to a constant, and this optimality cannot be achieved by uniform time discretizations. %U http://arxiv.org/abs/math/0604600v1