Comment on “ Nested stochastic simulation algorithm for chemical kinetic systems with disparate rates ” [ JCP 123 , 194107 ( 2005 ) ]

The slow-scale stochastic simulation algorithm (ssSSA) proposed in [J. Chem. Phys. 122, 014116 (2005)] and the nested stochastic simulation algorithm (nSSA) proposed in [J. Chem. Phys. 123,194107 (2005)] are closely related approximate simulation procedures aimed at speeding up the stochastic simulation of stiff chemical systems, i.e., systems that evolve through fast and slow dynamical modes with the fast mode being stable. This Comment aims to clarify some misconceptions that have arisen over the relationship between the ssSSA and the nSSA as regards both their theoretical foundations and their practical implementations. Submitted as T6.06.150 to The Journal of Chemical Physics (Version of 15 Jan 2007) a) Author to whom correspondence should be addressed.