Dependent parameters whose requirements are not satisfied are represented by a scalar NA
in the elements of x of the return value.
getOptPathEl(op, index)
| op | OptPath  | 
    
|---|---|
| index | (  | 
    
List with elements x (named list), y (named numeric),
dob integer(1), eol integer(1).
The elements error.message (character(1)),
exec.time (numeric(1)) and extra (named list) are
there if the respective options in OptPath() are enabled.
Other optpath: 
OptPath,
addOptPathEl(),
getOptPathBestIndex(),
getOptPathCols(),
getOptPathCol(),
getOptPathDOB(),
getOptPathEOL(),
getOptPathErrorMessages(),
getOptPathExecTimes(),
getOptPathLength(),
getOptPathParetoFront(),
getOptPathX(),
getOptPathY(),
setOptPathElDOB(),
setOptPathElEOL()