Length limit of monotone_constraints



I am running xgboost v0.82 on a linux box by using R 3.5.1.

My data has more than 2100 attributes, and I would like to set monotone constraint for each of them. Then it popped up the error message.

When I limited the number of attributes and set the monotone_constraints to the corresponding attributes, it worked. I tried just using the first 1024 attributes, it worked.

What is the limits for the monotone constraints? Can we set it to a larger number.