SSmicmen {stats} | R Documentation |
This selfStart
model evaluates the Michaelis-Menten model and
its gradient. It has an initial
attribute that
will evaluate initial estimates of the parameters Vm
and K
SSmicmen(input, Vm, K)
input |
a numeric vector of values at which to evaluate the model. |
Vm |
a numeric parameter representing the maximum value of the response. |
K |
a numeric parameter representing the |
a numeric vector of the same length as input
. It is the value of
the expression Vm*input/(K+input)
. If both
the arguments Vm
and K
are
names of objects, the gradient matrix with respect to these names is
attached as an attribute named gradient
.
JosÃ© Pinheiro and Douglas Bates
PurTrt <- Puromycin[ Puromycin$state == "treated", ] SSmicmen(PurTrt$conc, 200, 0.05) # response only Vm <- 200; K <- 0.05 SSmicmen(PurTrt$conc, Vm, K) # response and gradient print(getInitial(rate ~ SSmicmen(conc, Vm, K), data = PurTrt), digits = 3) ## Initial values are in fact the converged values fm1 <- nls(rate ~ SSmicmen(conc, Vm, K), data = PurTrt) summary(fm1) ## Alternative call using the subset argument fm2 <- nls(rate ~ SSmicmen(conc, Vm, K), data = Puromycin, subset = state == "treated") summary(fm2)