0

I want to use the artificial intelligence algorithm to choose the appropriate copula function to build a mixture of copula-based on the initial sample data. I plan to choose 2 to 3 of the following six alternative copula functions to form a mixture copula: Gaussian, t, Clayton, Gumbel, Frank, and Joe copula. Initially, I planned to choose the first 2/3 copula functions by relying on the AIC criteria, but the effect was not good. So, is there any good AI algorithm that can implement this idea, Thanks!

library(copula)
### Input three-dimension data :
x1 <- rnorm(n=1000,mean = 0.5,sd = 0.1)
x2 <- rlnorm(n = 1000,meanlog = 0.5,sdlog = 0.01)
x3 <- runif(n = 1000,min = 0.2,max = 0.8)
data<-matrix(c(x1,x2,x3),1000,3)
data01<-pobs(data)
###First,Calculate copula parameters and AIC values
### noramla copula 
nor.cop <- fitCopula(normalCopula(dim = 3), data1)
param_nor<-nor.cop@estimate
AIC_nor <- (-2)*(nor.cop@loglik)+2
### t copula
t.cop <- fitCopula(tCopula(dim = 3), data1)
param_t<- t.cop@estimate
AIC_t <- (-2)*(t.cop@loglik)+4
###clayton copula
clay.cop <- fitCopula(claytonCopula(dim = 3), data1)
param_cla<- clay.cop@estimate
AIC_cla <- (-2)*(clay.cop@loglik)+2
# alpha = 12.0343
###gumbel copula 
gum.cop <- fitCopula(gumbelCopula(dim = 3), data1)
param_gum <- gum.cop@estimate
AIC_gum <- (-2)*(gum.cop@loglik)+2
# alpha = 7.02198
###frank copula
fra.cop <- fitCopula(frankCopula(dim = 3), data1)
param_fra <- fra.cop@estimate
AIC_fra <- (-2)*(fra.cop@loglik)+2
###joe copula
joe<-fitCopula(joeCopula(dim = 3),data1)
param_joe<- joe@estimate
AIC_joe <- (-2)*(joe@loglik)+2
###is any AI algorithm to select copula to construct the mixture
###OUTPUT:Suitable 2-3 copula functions 
asked Nov 9, 2023 at 2:18
2
  • 2
    It would be best to fit different mixture copula models to your data. For each model, you need to calculate the AIC and then select the best-fit model based on the AIC. The copula mixture model is a complex task. You should read some publications to get a good idea of this topic. Happy to help with any further questions :) Commented Nov 9, 2023 at 4:30
  • 1
    Thanks!Your advice is very enlightening to me. Commented Nov 9, 2023 at 10:12

0

Know someone who can answer? Share a link to this question via email, Twitter, or Facebook.

Your Answer

Draft saved
Draft discarded

Sign up or log in

Sign up using Google
Sign up using Email and Password

Post as a guest

Required, but never shown

Post as a guest

Required, but never shown

By clicking "Post Your Answer", you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.