Functions to convert between EY, ARI and AEP see https://tonyladson.wordpress.com/2017/07/04/converting-between-ey-aep-and-ari/

Convert_frequency.R

AEP2ARI <- function(AEP){
  1/-log(1-AEP)
}

ARI2AEP <- function(ARI){
  (exp(1/ARI) - 1)/exp(1/ARI)
}

EY2AEP <- function(EY){
  ARI2AEP(1/EY)
}
  


test_ARI <- c(0.17,  0.25,  0.33,  0.5,     1, 1.44,  2,    4.48, 5,  9.49, 20, 50, 100)
test_AEP <- c(99.75, 98.17, 95.02, 86.47, 63.21, 50, 39.35, 20,  18.13, 10, 5, 2, 1)/100
test_EY <- c(12, 6, 4, 3, 2, 1)
  
ARI2AEP(test_ARI)
AEP2ARI(test_AEP)
EY2AEP(test_EY)

data_frame(EY = 1/test_ARI, 
           AEP = test_AEP, 
           AEP_check = ARI2AEP(test_ARI),
           AEP_1inX = 1/AEP, 
           ARI = test_ARI,
           ARI_check = AEP2ARI(test_AEP))