#file stochastic_decay.ode
#stochastic implementation (Gillespie SSA) of a collection of spontaneously
#decaying molecules.
#Figure 7.38

#the network is simply  X -> . with propensity a=k N_x, where N_x is the
#number of molecules of X

#set propensity parameter
par k=1
#
#set initial condition for molecule count X, and for elapsed time tr.
#
init X=100, tr=0
#
#set reaction propensity
#
a=k*X
#
# set the update rule for tr
#
tr'=tr+log(1/ran(1))/a
#
#set the update rules for molecule abundance
X'=X-1
#
# set the total number of steps to be taken
@ total=100
#
# set the model as discete-time (update rule-based)
@ meth=discrete
#
# set the plotting default to be X against tr
@ xp=tr,yp=X, xlo=0,xhi=10,ylo=0,yhi=100
#
done
#