#tyson14



#reactions
r1:
 $pool = {1.0}R
  env * k1 * S
r2:
 {1.0}R = $pool
  env * k2 * R * X
r3:
 $pool = {1.0}X
  env * k3 * S
r4:
 {1.0}X = $pool
  env * k4 * X


#parameters
k1 = 2.0
k2 = 2.0
k3 = 1.0
k4 = 1.0
tau = 4.0
env = 1.0


#initial values
R = 1
X = 0.0


#assignment rules
!F S = 1.0 * floor(time / tau)