drmc function

Sets control arguments

Set control arguments in the control argument in the function 'drm'.

drmc(constr = FALSE, errorm = TRUE, maxIt = 500, method="BFGS", 
  noMessage = FALSE, relTol = 1e-07, rmNA=FALSE, useD = FALSE, 
  trace = FALSE, otrace = FALSE, warnVal = -1, dscaleThres = 1e-15, rscaleThres = 1e-15)

Arguments

• constr: logical. If TRUE optimisation is constrained, only yielding non-negative parameters.
• errorm: logical specifying whether failed convergence in drm should result in an error or only a warning.
• maxIt: numeric. The maximum number of iterations in the optimisation procedure.
• method: character string. The method used in the optimisation procedure. See optim for available methods.
• noMessage: logical, specifying whether or not messages should be displayed.
• relTol: numeric. The relative tolerance in the optimisation procedure.
• rmNA: logical. Should NAs be removed from sum of squares used for estimation? Default is FALSE (not removed).
• useD: logical. If TRUE derivatives are used for estimation (if available).
• trace: logical. If TRUE the trace from optim is displayed.
• otrace: logical. If TRUE the output from optim is displayed.
• warnVal: numeric. If equal to 0 then the warnings are stored and displayed at the end. See under 'warn' in options. The default results in suppression of warnings.
• dscaleThres: numeric value specifying the threshold for dose scaling.
• rscaleThres: numeric value specifying the threshold for response scaling.

Returns

A list with 8 components, one for each of the above arguments.

Author(s)

Christian Ritz

Note

The use of a non-zero constant bcAdd may in some cases make it more difficult to obtain convergence of the estimation procedure.

Examples

### Displaying the default settings
drmc()  

### Using 'method' argument
model1 <- drm(ryegrass, fct = LL.4())

model2 <- drm(ryegrass, fct = LL.4(),
control = drmc(method = "Nelder-Mead"))