I have a question about the use of the "mu" parameter in the functions
StdDev, VaR e CVaR.
As reference data we can use data in the paper "Vignette: Portfolio
Optimization with CVaR budgets in PortfolioAnalytics".
If we use the default parameters for "mu" and "sigma", there is a
match between
constrained_objective( w = rep(1/4,4) , R = indexes, portfolio = ObjSpec)
[,1]
[1,] 0.1253199
as explained by the authors.
If I insert a user-defined sigma matrix for the "sigma" parameter, the
match is still there between this two exspressions. If I insert a
user-defined vector for the "mu" parameter (for example "mu=rep(0.01, 4)",
the result of the two exspressions is the same only for portafolio with
risk objective function StdDev and VaR, not for CVaR.
VaR case: