[R] coxme - fitting random treatment effect nested within centre

Dear all, I am using coxme function in Kinship library to fit random treatment effect nested within centre. I got 3 treatments (0,1,2) and 3 centres. I used following commands, but got an error. ugroup=paste(rep(1:3,each=3),rep(0:2,3),sep='/')

Re: [R] coxme - fitting random treatment effect nested within centre

included message Dear all, I am using coxme function in Kinship library to fit random treatment effect nested within centre. I got 3 treatments (0,1,2) and 3 centres. I used following commands, but got an error. ugroup=paste(rep(1:3,each=3),rep(0:2,3),sep='/')