S == over(c, (1 + exp(-z * A + f)))

1 |

The format is: List of 8 $ name : "Logistic function" $ formula : expression(S == over(c, (1 + exp(-z * A + f)))) $ paramnumber: 3 $ paramnames : "c" "z" "f" $ parLim : "Rplus" "Rplus" "R" $ fun : model function $ rssfun : Residual Sum of Squares function $ init : initial values calculation $ form : a formula object for further calculations

This model is sigmoid asymptotic. Parameter c is the upper asymptote. The function is symmetrical about the inflection point. The curve has a lower asymptote of zero, and the intersection with the y-axis depends on all three parameters. Thus it never goes through the origin. For further details and documentation please see the online documentation at http://mmsar.r-forge.r-project.org/

Ratkowsky (1990), Tjørve (2003).

Ratkowsky, D.A. (1990) Handbook of nonlinear regression models. Marcel Dekker, New York.

Tjørve, E. (2003) Shapes and functions of species–area curves: a review of possible models. Journal of Biogeography, 30, 827–835.

1 2 |

Questions? Problems? Suggestions? Tweet to @rdrrHQ or email at ian@mutexlabs.com.

Please suggest features or report bugs with the GitHub issue tracker.

All documentation is copyright its authors; we didn't write any of that.

Embedding an R snippet on your website

Add the following code to your website.

For more information on customizing the embed code, read Embedding Snippets.