result from ODE
DINTDY- T (=R1) illegal
In above message, R1 = 16
T not in interval TCUR - HU (= R1) to TCUR (=R2)
In above message, R1 = 15.9441, R2 = 15.9441
DINTDY- T (=R1) illegal
In above message, R1 = 17
T not in interval TCUR - HU (= R1) to TCUR (=R2)
In above message, R1 = 15.9441, R2 = 15.9441
DLSODA- Trouble in DINTDY. ITASK = I1, TOUT = R1
In above message, I1 = 1
In above message, R1 = 17
我尝试更改模拟的起始值和持续时间,但是似乎无效。我还尝试通过运行单个时间步来调试ode,但是没有运气。
图书馆(解救)
# C = coral, measured as the biomass of a single head
# D = damselfish, a fish that dwells inside the coral, eats plankton, and
# fertilizes the coral with its waste products
# H = hawkfish, a fish that dwells on the outside of the coral, is an
# aggressive predator and can competitively displace P
# U = uberpredator, a fish that lives outside the coral and preys upon both
# P and H
params<- c(
# CORAL:
g_0 = 0.1, #fertilization-enhancement to coral growth rate
g_1 = 1, #base growth rate of coral
#n_D = .02, # Excretion rate of damselfish
#n_H = .005, # Excretion rate of hawkfish
#h_N = 10*n_D, # Half-saturation of excretion
#nu = n_H/n_D, # Scaling of hawkfish benefits relative to damselfish
#eta = h_N/n_D, # Scaling of half-saturation to damselfish
m = .01, #mortality of coral
# DAMSELFISH:
r_D = .3, # base growth rate of planktivore
k_D = 1, #carrying capacity per unit coral biomass of damselfish
#exp_D = 1, #how carrying capacity of damselfish scales with coral size
alpha_DH = 2, # competitive effects of damselfish on hawkfish
a_D = 0, #attack rate of uberpredator on damselfish
# HAWKFISH
r_H = .2, #base growth rate of hawkfish
k_H = 1, #carrying capacity per unit coral surface area of hawkfish
#exp_H = 1, #how carrying capcity of the hawkfish scales with coral size
alpha_HD = .1, #competitive effects of hawkfish on planktivore
a_H = .15 #attack rate of uberpredator on hawkfish
)
#this model has no uberpredator
cmod <- function(t,y,params)
{
C <- y[1] #coral biomass
D <- y[2] #damselfish biomass
H <- y[3] #hawkfish biomass
with(as.list(params), {
# modified for saturating growth rate and density dependence:
dCdt = C*(g_1*(D+H)+g_0-m)
#Second equation: Damselfish biomass
dDdt = r_D*D*(k_D*C-D-alpha_HD*H)/(k_D*C)-a_D*D
#Third equation: Hawkfish biomass
dHdt = r_H*H*(k_H*C-H-alpha_DH*D)/(k_H*C)-a_H*H
return(list(c(dCdt,dDdt,dHdt)))
})
}
#simulation details
t <- seq(0,10000,by=1) #duration of simulation
N.init <- c(C=1,D=2,H=2)
sim1 <- ode(N.init,t,cmod,params)
我希望获得焦点参数C,H,D的结果列表