"Extract.emaxsim" {clinDR} R Documentation

## Extract a simulation from the output of emaxsim

### Description

Extract a simulated data set from the output of emaxsim. Data are re-created using the stored random number seed.

### Usage

## S3 method for class 'emaxsim'
x[i, ...]


### Arguments

 x Output object from emaxsim i Simulation replication to extract ... Parameters passed to other functions (none currently)

### Details

Re-creates the ith simulated data set for subsequent analyses. Also returns all analyses done for the ith data set in emaxsim

### Value

A list is returned with class(emaxsimobj) containing:

 y Response vector dose Doses corresponding to y pop Population parameters; type of parameter depends on constructor function generating study data. popSD Vector containing the population SD used to generate continuous data. NULL for binary data. init Starting Emax parameters est4 4-parmameter Emax fit (ed50,lambda,emax,e0). NA if failed to converge or 3-parameter model requested. est3 3-parmameter Emax fit (ed50,emax,e0). NA if failed to converge or 4-parameter model successfully fit. estA Alternative parameter estimates. NA if Emax model fit successfully vc The variance-covariance matrix of the model parameters for the selected model. residSD The residual SD based on the selected model. bigC bigC= TRUE if the primary fit (from modType) yielded an ED50 > ED50 upper limit. negC negC= TRUE if the primary fit (from modType) yielded a negative ED50 estimate< ED50 lower limit modType When modType=4, the fitting begins with the 4 parameter model. If estimation fails or modType=3, the 3-parameter estimation is applied. If it fails, a best-fitting model linear in its parameters is selected. fit Output of model determined by fitType fitType Character vector with "4", "3", "L", "LL", or "E" for 4-Emax, 3-Emax, linear, log-linear, or exponential when an alternative model is selected. ed50cutoff Upper allowed limit for ED50 estimates. ed50lowcutoff Lower allowed limit for the ED50 estimates. switchMod If switchMod is TRUE, the algorithm substitutes a simpler model if (1) convergence is not achieved, (2) the information matrix is not positive definite at the converged values, (3) the ED50 estimates are outside the cutoff bounds. If switchMod is F, only conditions (1) or (2) cause a simpler model to be used. PL T if the 'plinear' algorithm in nls converged predpop Population means for each dose group dm Vector containing dose group means dsd Vector containing dose group SDs fitpred Dose groups means estimated from the model sepred SEs for estimates in fitpred sedif SEs for model-based estimates of difference with placebo pVal, selContrast P-value and contrast selected from MCP-MOD test idmax Index of default dose group for comparison to placebo

### Note

Extraction from a simulation object requires re-creation of the simulated data set. If the extracted object is to be used more than once, it is more efficient to save the extracted object than reuse [].

### Author(s)

Neal Thomas

emaxsim, print.emaxsimobj, plot.emaxsimobj, update.emaxsimobj

### Examples


## Not run:
## code change random number seed

nsim<-50
idmax<-5
doselev<-c(0,5,25,50,100)
n<-c(78,81,81,81,77)

### population parameters for simulation
e0<-2.465375
ed50<-67.481113

dtarget<-100
diftarget<-9.032497
emax<-solveEmax(diftarget,dtarget,log(ed50),1,e0)

sdy<-7.967897
pop<-c(log(ed50),emax,e0)
meanlev<-emaxfun(doselev,pop)

###FixedMean is specialized constructor function for emaxsim
gen.parm<-FixedMean(n,doselev,meanlev,sdy)

D1 <- emaxsim(nsim,gen.parm,modType=3)
e49<-D1[49]                  #### extract 49th simulation

## End(Not run)



[Package clinDR version 2.3.5 Index]