Optimizing daylight simualtion for speed and accuracy

A study by Reinhart and Herkel showed term predictions of daylight availability in architectural spaces should take the conditions  of all individual time steps into account. However, most contemporary simulation tool algorithms require such long computation times that it  is  impractical  or  even  unrealistic to simulation of the daylight penetration for each time step. This  paper  discusses  two  adaptations of a known  algorithm,  radiosity, that  bring down the required  computation time for an annual prediction from the order of days to the order of seconds.