-------- Original Message -------- Subject: Re: Question on shrink_bounding_box Date: Sun, 3 Jul 2005 14:17:55 +0100 From: Pedro Vasconcelos <pbv@st-andrews.ac.uk> Organization: University of St Andrews To: Roberto Bagnara <bagnara@cs.unipr.it> References: <20050702195917.22ba8af3.pbv@st-andrews.ac.uk> <42C7DBEA.7040404@cs.unipr.it> On Sun, 03 Jul 2005 14:36:58 +0200 Roberto Bagnara <bagnara@cs.unipr.it> wrote:

what the shrink_bounding_box() method does is the following:

1) the smallest bounding box containing the polyhedron is computed; then 2) the bounding box provided by the caller is (destructively) intersected with the one computed in step 1 by using only the methods of `Box' listed in the documentation.

Notice that there is no way shrink_bounding_box() can obtain information from the `box' parameter. This interface and semantics allow for maximum efficiency, yet minimizing the requirements we impose on the `box' argument. Any suggestion about how to improve the documentation is welcome

OK, this makes perfect sense to me now! The operation I want can then be obtained by first constructing a polyhedron from the bounding box, intersecting two polyhedra and then using shrink_bounding_box to get the resulting box. I think your explanation above is very clear and should be added to the PPL documentation. Cheers, Pedro -- Prof. Roberto Bagnara Computer Science Group Department of Mathematics, University of Parma, Italy http://www.cs.unipr.it/~bagnara/ mailto:bagnara@cs.unipr.it