I have two categorical variables (A and B) that I want to add as Random factor in GLIMMIX. A has 4 categories and B has 44. Finally B is nested in A.
When I added as random factor, the model results said that "Estimate G matrix is not positive definite". How can I solve this problem? Did I add the variables in a correct way??
proc GLIMMIX data=Resumen;
class A B Cat;
model total = intra flux Cat length / dist=poisson link=log solution;
random B B(A);