standrm: Dose-response models with rstan

In daniel-gerhard/standrc: Dose-response curves with stan

Description

Formula interface for fitting dose-response curves with rstan

Usage

standrm(formula, data, fct, curveid = NULL, random = NULL,
        priors = standrc_priors(), ...)

Arguments

formula	A two-sided formula with response and dose covariate names
data	A dataframe containing the variables in the model
fct	A drc model function.
curveid	A two-sided formula with parameter names (b + c + d) on the left and a factor name on the right hand side, defining several clusters, modelled as fixed effects
random	A two-sided formula with parameter names (b + c + d) on the left and a factor name on the right hand side, defining several clusters, modelled as random effects
priors	A list with prior definitions, see standrc_priors
...	Additional arguments passed to function stan in ackage rstan

Details

The parameterization of the drc model functions is changed, modelling the slope and the asymmetry parameter on a logarithmic scale and allowing the lower and upper asymptotes to swap parameters. This might be problematic with three-parameter functions, fixing a specific asymptote by the fixed argument in a more complex model might be a better solution. Random effect parameters can be specified even when the fixed effects counterpart is fixed at a specific value, e.g. allowing cluster variation around a lower asymptote fixed at a response value of 0.

Value

stan_dat	rstan compatible list containing the data
model	A character vector containing the stan model
stan	S4 output of rstan containing the samples from the posterior distributions
pars	Character vector with fixed effects parameter names
random	Character vector with random effects parameter names

Author(s)

Daniel Gerhard

Examples

## Not run: 
data(spinach)
head(spinach)

m <- standrm(SLOPE ~ DOSE, data=spinach, 
             fct=LL.5(fixed=c(NA, NA, NA, NA, 0)), 
             curveid=b + c + e ~ HERBICIDE, 
             random=c + e ~ CURVE, 
             iter=3000, chains=4)
print(m)
ranef(m)
VarCorr(m)

ED(m, respLev=c(25, 50, 75))


## End(Not run)

daniel-gerhard/standrc documentation built on May 14, 2019, 3:39 p.m.