Dear Sir/Madam, Thank you for developing such a great library. I am currently learning how to use it. I have a question as follows. Could you give me some suggestions? The question is as follows. Given a NNC_Polyhedron, I want to merge two dimensions in it, say dim1 and dim2. Then, my current code is _polyhedron.add_constraint(PPL::Variable(dim1) == PPL::Variable(dim2));

_polyhedron.remove_space_dimensions( ​PPL::Variables_Set(​ PPL::Variable(dim1) ​)​ );

When _polyhedron is very large, say 60 dimensions, the merging operation becomes extremely slow. Is there a better way to merge dimensions? There is a operation called fold_space_dimensions. But I am not sure about its effect. Thank you very much! Best Regards, Li Li -- ( ​Dr ) Li Li Email : lilissun@gmail.com iTrust, Singapore University of Technology and Design