mirror of https://github.com/CGAL/cgal
81 lines
2.5 KiB
C++
81 lines
2.5 KiB
C++
// Copyright (c) 1997-2001 ETH Zurich (Switzerland).
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// All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org); you may redistribute it under
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// the terms of the Q Public License version 1.0.
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// See the file LICENSE.QPL distributed with CGAL.
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//
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// Licensees holding a valid commercial license may use this file in
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// accordance with the commercial license agreement provided with the software.
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//
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// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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//
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// $URL: svn+ssh://gaertner@scm.gforge.inria.fr/svn/cgal/trunk/QP_solver/include/CGAL/QP_functions.h $
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// $Id: QP_functions.h 33922 2006-09-05 12:32:25Z gaertner $
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//
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//
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// Author(s) : Bernd Gaertner <gaertner@inf.ethz.ch>
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#ifndef CGAL_QP_FUNCTIONS_H
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#define CGAL_QP_FUNCTIONS_H
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#include <CGAL/iterator.h>
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#include <CGAL/QP_solver.h>
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#include <CGAL/QP_models.h>
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CGAL_BEGIN_NAMESPACE
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template <class Q>
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bool QP_is_in_equational_form (const Q& qp) {
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// check whether all constraints are equality constraints
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typename Q::R_iterator r = qp.r();
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typename Q::R_iterator r_end = r + qp.m();
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for (; r < r_end; ++r)
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if (*r != CGAL::EQUAL) return false;
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return true;
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}
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template <class Q, class ET>
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bool QP_has_full_row_rank (const Q& qp, const ET& dummy) {
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// we solve the following auxiliary LP, using exact type ET:
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// --------
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// min 0
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// A x == 0
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// x >= 0
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// --------
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// Then A has full row rank if and only if all artificials
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// have left the basis after phase I; the QP_solver diagnostics
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// tells us this
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//
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// auxiliary LP type
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typedef Const_oneset_iterator<typename Q::value_type> C_iterator;
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typedef Const_oneset_iterator<typename Q::value_type> B_iterator;
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typedef Const_oneset_iterator<CGAL::Comparison_result> R_iterator;
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typedef Nonnegative_LP_from_iterators
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<typename Q::A_iterator, B_iterator, R_iterator, C_iterator> LP;
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// auxiliary LP
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LP lp (qp.n(), qp.m(),
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qp.a(), B_iterator(0), R_iterator(CGAL::EQUAL), C_iterator(0));
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// solver Tags
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typedef QP_solver_impl::QP_tags<
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Tag_true, // Is_linear
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Tag_true, // Is_symmetric
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Tag_false, // Has_equalities_only_and_full_rank (we don't know it yet)
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Tag_true> // Is_in_standard_form
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Tags;
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// solver type
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typedef QP_solver<LP, ET, Tags> Solver;
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// now solve auxiliary LP and compute predicate value
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Solver solver (lp);
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return !solver.diagnostics.redundant_equations;
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}
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CGAL_END_NAMESPACE
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#endif // CGAL_QP_FUNCTIONS_H
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