[PPL-devel] Question on Merging Two Dimensions in a NNC_Polyhedron.

[Li Li]

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 at gmail.com
iTrust, Singapore University of Technology and Design
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