In the past few years, LEDs have become a particularly popular and attractive light source, due to their high energy efficiency and long life time. Moreover, LEDs offer superior flexibility in controlling the output light patterns. This paper addresses the inverse problem of how to render an appropriate illumination for multiple users by controlling the dimmings of a dimmable LED array. Each of the users has different task light preferences and they are at different locations of an indoor environment. To solve this optimization problem, we invoke adaptive simulated annealing. The trade-off curve between reducing energy consumption and increasing user comfort is presented at the end of this paper