SSlogis
Self-Starting Nls Logistic Model
This selfStart model evaluates the logistic
function and its gradient. It has an initial attribute that
creates initial estimates of the parameters Asym,
xmid, and scal.
- Keywords
- models
Usage
SSlogis(input, Asym, xmid, scal)Arguments
- input
- a numeric vector of values at which to evaluate the model.
- Asym
- a numeric parameter representing the asymptote.
- xmid
- a numeric parameter representing the
xvalue at the inflection point of the curve. The value ofSSlogiswill beAsym/2atxmid. - scal
- a numeric scale parameter on the
inputaxis.
Value
-
a numeric vector of the same length as
input. It is the value of
the expression Asym/(1+exp((xmid-input)/scal)). If all of
the arguments Asym, xmid, and scal are
names of objects the gradient matrix with respect to these names is attached as
an attribute named gradient.
See Also
Examples
library(stats)
Community examples
Looks like there are no examples yet.