mixture.Rd'mixture' fits a concentration addition, Hewlett or Voelund model to data from binary mixture toxicity experiments.
mixture(object, model = c("CA", "Hewlett", "Voelund"), start, startm, control = drmc())
| object | object of class 'drc' corresponding to the model with freely varying EC50 values. |
|---|---|
| model | character string. It can be "CA", "Hewlett" or "Voelund". |
| start | optional numeric vector supplying starting values for all parameters in the mixture model. |
| startm | optional numeric vector supplying the lambda parameter in the Hewlett model or the eta parameters (two parameters) in the Voelund model. |
| control | list of arguments controlling constrained optimisation (zero as boundary), maximum number of iteration in the optimisation, relative tolerance in the optimisation, warnings issued during the optimisation. |
The function is a wrapper to drm, implementing the models described in Soerensen et al. (2007).
See the paper for a discussion of the merits of the different models.
Currently only the log-logistic models are available. Application of Box-Cox transformation is not yet available.
An object of class 'drc' with a few additional components.
Ritz, C. and Streibig, J. C. (2014) From additivity to synergism - A modelling perspective Synergy, 1, 22--29.