The main function is icweib(), which fits a stratified Weibull
proportional hazards model for left censored, right censored, interval censored,
and non-censored survival data. We parameterize the Weibull regression model
so that it allows a stratum-specific baseline hazard function, but where the
effects of other covariates are assumed to be constant across strata.
Please refer to Xiangdong Gu, David Shapiro, Michael D. Hughes and
Raji Balasubramanian (2014)
Stratified Weibull Regression Model
For details of the proposed method, please refer to our R Journal artile