How to obtain AIC with conditional logistic regression using R?

Question

I am fitting a conditional logistic regression model with 1:4 controls using R. I wish to obtain AIC from the model. How can I extract the appropriate parameters based on object m?

library(survival)
m<-clogit(cc~exp+ factor1+ factor2 + strata(stratum),data=data1)

Thank you for your help.

Answer 1

It seems you must do it manually, so something like this:

2*length(m$coefficients)-2*(m$loglik[2])