R/ptp3.R

In twopiece: The family of two piece distributions

ptp3 <-
function(x, mu, par1, par2, FUN,param = "tp", log.p = FALSE ){
if(param == "tp")
  {
    ifelse( par1 > 0  & par2 > 0,
      CDF  <-  ifelse( x < mu ,2*par1*FUN( (x-mu)/par1, log.p=F)/(par1+par2),( par1 + par2*(2*FUN( (x-mu)/par2, log.p=F)-1) )/( par1+par2)),
      CDF  <- 'invalid arguments: par1 or/and par2 is/are not positive in the parametrization tp' )
  }
if(param == "eps")
  { 
sigma  = par1 ; gamma  = par2
ifelse( sigma > 0 & abs(gamma) < 1,
      CDF  <- ifelse( x < mu, (1+gamma)*FUN( (x-mu)/(sigma*(1+gamma)), log.p=F ),gamma + (1-gamma)*FUN( (x-mu)/(sigma*(1-gamma)), log.p=F ) ) ,
      CDF  <- 'invalid arguments: par1 is not positive or/and abs(par2) is not less than 1 in the parametrization eps' )
}
if(param == "isf")
  { 
    sigma  = par1; gamma  = par2
    ifelse( sigma > 0 & gamma > 0,
      CDF <-  ifelse( x < mu,2*gamma^2*FUN( (x-mu)/(sigma*gamma), log.p=F )/(1+gamma^2),  ( gamma^2-1 + 2*FUN( (x-mu)/(sigma/gamma), log.p=F)  )/(1+gamma^2)) ,
      CDF <- 'invalid arguments: par1 or/and par2 is/are not positive in the parametrization isf' )
    
}
   ifelse( is.numeric(CDF),ifelse( log.p, return(log(CDF)), return(CDF) ), CDF )
}