This paper documents our development and evaluation of a numerical solver for systems of sparsely linked ordinary differential equations in which the connectivity between equations is determined by a directed tree.

Small, S.J., L.O. Jay, R. Mantilla, R. Curtu, L.K. Cunha, M. Fonley, and W.F. Krajewski. “An Asynchronous Solver for Systems of ODEs Linked by a Directed Tree Structure,” Advances in Water Resources, 53, pp. 23–32, 2013.