62 lines
1.8 KiB
C
62 lines
1.8 KiB
C
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// Copyright (c) 2005-2008 INRIA Sophia-Antipolis (France).
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// All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org)
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//
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// $URL: https://github.com/CGAL/cgal/blob/v5.1/Filtered_kernel/include/CGAL/Robust_construction.h $
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// $Id: Robust_construction.h 52164b1 2019-10-19T15:34:59+02:00 Sébastien Loriot
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// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
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//
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// Author(s) : Sylvain Pion, Mariette Yvinec, Laurent Rineau
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#ifndef CGAL_ROBUST_CONSTRUCTION_H
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#define CGAL_ROBUST_CONSTRUCTION_H
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#include <CGAL/config.h>
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namespace CGAL {
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// This template class is a functor adaptor targetting geometric constructions.
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//
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// They are "robust" in the following sense : the input and output are
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// approximate (doubles), but the internal computation tries to guarantees the
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// approximation quantitatively.
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//
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// This is especially useful in order to minimize the bad things that happen
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// in close-to-degenerate cases (e.g. computing the circumcenter of an almost
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// flat tetrahedron).
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//
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// The implementation strategy is to:
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// - convert the input to Lazy kernel objects
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// - perform the computation with it
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// - convert back to double in a guaranteed way (since Lazy_exact_nt guarantees
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// a precision on to_double).
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// TODO :
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// - possible improvement by avoiding the constructions of Lazy_exact_nt's.
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template <class EC, class A2E, class E2A, class Result_type>
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class Robust_construction
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{
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EC ec;
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A2E a2e;
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E2A e2a;
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public:
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typedef Result_type result_type;
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typedef EC Exact_construction;
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typedef A2E Approximate_to_exact_converter;
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typedef E2A Exact_to_approximate_converter;
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template <typename... Args>
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result_type
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operator()(const Args&... args) const
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{ return e2a(ec(a2e(args)...)); }
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};
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} //namespace CGAL
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#endif // CGAL_ROBUST_CONSTRUCTION_H
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