The authors of this paper introduce an interesting and effective method to solve the “radiative transport equation in inhomogeneous participating media” using a cluster of graphics processing units (GPUs) and allowing interactive source placement.

Particularly interesting is the bootstrapping algorithm that improves the convergence of the iterations and reduces their discretization artifacts. Furthermore, it makes the parallel implementation more efficient. The algorithm is well designed and takes into account the particularities of GPU programming--for example, by not exchanging boundary conditions in every iteration cycle in order to eliminate the communication bottleneck

While the paper deals professionally with a very narrow topic, it will interest several research communities, including GPU programming, computer graphics, and computational methods.