425 lines
14 KiB
C
425 lines
14 KiB
C
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// Copyright (c) 2000,2001
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// Utrecht University (The Netherlands),
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// ETH Zurich (Switzerland),
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// INRIA Sophia-Antipolis (France),
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// Max-Planck-Institute Saarbruecken (Germany),
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// and Tel-Aviv University (Israel). All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public License as
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// published by the Free Software Foundation; either version 3 of the License,
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// or (at your option) any later version.
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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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// $URL$
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// $Id$
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// SPDX-License-Identifier: LGPL-3.0+
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//
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//
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// Author(s) : Michael Seel
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#ifndef CGAL_VECTORHD_H
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#define CGAL_VECTORHD_H
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#include <CGAL/basic.h>
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#include <CGAL/Quotient.h>
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#include <CGAL/Kernel_d/Tuple_d.h>
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#include <CGAL/Kernel_d/PointHd.h>
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#include <CGAL/Kernel_d/Aff_transformationHd.h>
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namespace CGAL {
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#define PointHd PointHd2
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template <class RT, class LA> class VectorHd;
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template <class RT, class LA>
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std::istream& operator>>(std::istream&, VectorHd<RT,LA>&);
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template <class RT, class LA>
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std::ostream& operator<<(std::ostream&, const VectorHd<RT,LA>&);
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/*{\Manpage {Vector_d}{R}{Vectors in d-space}{v}}*/
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/*{\Msubst
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Hd<RT,LA>#_d<R>
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VectorHd#Vector_d
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PointHd#Point_d
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Quotient<RT>#FT
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}*/
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template <class _RT, class _LA>
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class VectorHd : public Handle_for< Tuple_d<_RT,_LA> > {
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typedef Tuple_d<_RT,_LA> Tuple;
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typedef Handle_for<Tuple> Base;
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typedef VectorHd<_RT,_LA> Self;
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using Base::ptr;
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using Base::copy_on_write;
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/*{\Mdefinition
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An instance of data type |\Mname| is a vector of Euclidean space in
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dimension $d$. A vector $r = (r_0,\ldots,r_{ d - 1})$ can be represented
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in homogeneous coordinates $(h_0,\ldots,h_d)$ of number type |RT|,
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such that $r_i = h_i/h_d$ which is of type |FT|. We call the
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$r_i$'s the Cartesian coordinates of the vector. The homogenizing
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coordinate $h_d$ is positive.
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This data type is meant for use in computational geometry. It realizes
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free vectors as opposed to position vectors (type |PointHd|). The
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main difference between position vectors and free vectors is their
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behavior under affine transformations, e.g., free vectors are
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invariant under translations.}*/
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const typename _LA::Vector& vector_rep() const { return ptr()->v; }
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_RT& entry(int i) { return ptr()->v[i]; }
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const _RT& entry(int i) const { return ptr()->v[i]; }
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void invert_rep() { ptr()->invert(); }
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VectorHd(const Base& b) : Base(b) {}
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public:
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/*{\Mtypes 4}*/
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typedef _RT RT;
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/*{\Mtypemember the ring type.}*/
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typedef Quotient<_RT> FT;
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/*{\Mtypemember the field type.}*/
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typedef _LA LA;
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/*{\Mtypemember the linear algebra layer.}*/
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typedef typename Tuple::Cartesian_const_iterator Cartesian_const_iterator;
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/*{\Mtypemember a read-only iterator for the Cartesian coordinates.}*/
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typedef typename Tuple::const_iterator Homogeneous_const_iterator;
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/*{\Mtypemember a read-only iterator for the homogeneous coordinates.}*/
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class Base_vector {};
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/*{\Mtypemember construction tag.}*/
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friend class PointHd<RT,LA>;
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friend class DirectionHd<RT,LA>;
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friend class HyperplaneHd<RT,LA>;
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/*{\Mcreation 4}*/
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VectorHd(int d = 0) : Base( Tuple(d+1) )
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/*{\Mcreate introduces a variable |\Mvar| of type |\Mname| in
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$d$-dimensional space.}*/
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{ if ( d > 0 ) entry(d) = 1; }
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VectorHd(int d, Null_vector) : Base( Tuple(d+1) )
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/*{\Mcreate introduces the zero vector |\Mvar| of type |\Mname| in
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$d$-dimensional space. There is a constant |CGAL::NULL_VECTOR| that
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can be used for the second argument.}*/
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{ if ( d > 0 ) entry(d) = 1; }
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template <class InputIterator>
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VectorHd(int d, InputIterator first, InputIterator last) :
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Base( Tuple(d+1,first,last) )
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/*{\Mcreate introduces a variable |\Mvar| of type |\Mname| in dimension |d|.
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If |size [first,last) == d| this creates a vector with Cartesian coordinates
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|set [first,last)|. If |size [first,last) == p+1| the range specifies the
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homogeneous coordinates $|H = set [first,last)| = (\pm h_0, \pm h_1, \ldots,
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\pm h_d)$ where the sign chosen is the sign of $h_d$.
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\precond |d| is nonnegative, |[first,last)| has |d| or |d+1| elements where the
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last has to be non-zero, and the value type of |InputIterator| is |RT|.}*/
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{ RT D = entry(d);
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if ( D == RT(0) ) entry(d) = 1;
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if ( D < RT(0) ) invert_rep();
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}
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template <class InputIterator>
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VectorHd(int d, InputIterator first, InputIterator last,
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const RT& D) : Base( Tuple(d+1,first,last,D) )
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/*{\Mcreate introduces a variable |\Mvar| of type |\Mname|
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in dimension |d| initialized to the vector with homogeneous
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coordinates as defined by |H = set [first,last)| and |D|:
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$(\pm |H[0]|, \pm|H[1]|, \ldots, \pm|H[d-1]|, \pm|D|)$. The sign chosen
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is the sign of $D$. \precond |D| is non-zero, the iterator range defines
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a $d$-tuple of |RT|, and the value type of |InputIterator| is |RT|. }*/
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{ CGAL_assertion_msg(D!=RT(0), "VectorHd::constructor: D must be nonzero.");
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if (D < RT(0)) invert_rep();
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}
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VectorHd(int d, Base_vector, int i) : Base( Tuple(d+1) )
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/*{\Mcreate returns a variable |\Mvar| of type |\Mname| initialized
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to the $i$-th base vector of dimension $d$. }*/
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{ entry(d) = 1;
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if ( d == 0 ) return;
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CGAL_assertion_msg((0<=i&&i<d),"VectorHd::base: index out of range.");
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entry(i) = 1;
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}
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VectorHd(const RT& x, const RT& y, const RT& w = 1)
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/*{\Mcreate introduces a variable |\Mvar| of type |\Mname| in
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$2$-dimensional space. }*/
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: Base( Tuple(x,y,w) )
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{ CGAL_assertion_msg((w != 0), "VectorHd::construction: w == 0.");
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if (w < 0) invert_rep();
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}
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VectorHd(int a, int b, int c = 1) :
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Base( Tuple((RT)a,(RT)b,(RT)c, MatchHelper()) )
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{ CGAL_assertion_msg((c != 0), "VectorHd::construction: w == 0.");
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if (c < 0) invert_rep();
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}
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VectorHd(const RT& x, const RT& y, const RT& z, const RT& w)
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/*{\Mcreate introduces a variable |\Mvar| of type |\Mname| in
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$3$-dimensional space. }*/
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: Base( Tuple((RT)x,(RT)y,(RT)z,(RT)w) )
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{ CGAL_assertion_msg((w!=0), "VectorHd::construction: w == 0.");
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if (w < 0) invert_rep();
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}
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VectorHd(int a, int b, int c, int d) :
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Base( Tuple((RT)a,(RT)b,(RT)c,(RT)d) )
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{ CGAL_assertion_msg((d!=0), "VectorHd::construction: w == 0.");
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if (d < 0) invert_rep();
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}
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VectorHd(const VectorHd<RT,LA>& p) : Base(p) {}
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~VectorHd() {}
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/*{\Moperations 5 3 }*/
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int dimension() const { return ptr()->size()-1; }
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/*{\Mop returns the dimension of |\Mvar|. }*/
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Quotient<RT> cartesian(int i) const
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/*{\Mop returns the $i$-th Cartesian coordinate of |\Mvar|.
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\precond $0 \leq i < d$.}*/
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{ CGAL_assertion_msg((0<=i && i<(dimension())), "VectorHd::cartesian():\
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index out of range.");
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return Quotient<RT>(entry(i), entry(dimension()));
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}
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Quotient<RT> operator[](int i) const { return cartesian(i); }
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/*{\Marrop returns the $i$-th Cartesian coordinate of |\Mvar|.
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\precond $0 \leq i < d$.}*/
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RT homogeneous(int i) const
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/*{\Mop returns the $i$-th homogeneous coordinate of |\Mvar|.
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\precond $0 \leq i \leq d$.}*/
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{ CGAL_assertion_msg((0<=i && i<=(dimension())), "VectorHd::homogeneous():\
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index out of range.");
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return entry(i);
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}
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Quotient<RT> squared_length() const
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/*{\Mop returns the square of the length of |\Mvar|. }*/
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{ RT nom = 0;
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for (int i = 0; i < dimension(); i++)
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nom += CGAL_NTS square(homogeneous(i));
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RT denom = CGAL_NTS square(homogeneous(dimension()));
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return Quotient<RT>(nom,denom);
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}
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Cartesian_const_iterator cartesian_begin() const
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/*{\Mop returns an iterator pointing to the zeroth Cartesian coordinate
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of |\Mvar|. }*/
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{ return Cartesian_const_iterator(ptr()->begin(),ptr()->last()); }
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Cartesian_const_iterator cartesian_end() const
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/*{\Mop returns an iterator pointing beyond the last Cartesian coordinate
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of |\Mvar|. }*/
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{ return Cartesian_const_iterator(ptr()->last(),ptr()->last()); }
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Homogeneous_const_iterator homogeneous_begin() const
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/*{\Mop returns an iterator pointing to the zeroth homogeneous coordinate
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of |\Mvar|. }*/
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{ return ptr()->begin(); }
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Homogeneous_const_iterator homogeneous_end() const
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/*{\Mop returns an iterator pointing beyond the last homogeneous
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coordinate of |\Mvar|. }*/
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{ return ptr()->end(); }
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inline PointHd<RT,LA> to_point() const;
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inline DirectionHd<RT,LA> direction() const;
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/*{\Mop returns the direction of |\Mvar|. }*/
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VectorHd<RT,LA> transform(const Aff_transformationHd<RT,LA>& t) const;
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/*{\Mop returns $t(v)$. }*/
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/*{\Mtext \headerline{Arithmetic Operators, Tests and IO}}*/
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VectorHd<RT,LA> scale(const RT& m, const RT& n) const
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{ int d = dimension();
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VectorHd<RT,LA> result(d);
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result.entry(d) = entry(d) * n;
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for (int i = 0; i < d; i++)
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result.entry(i) = entry(i) * m;
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return result;
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}
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void self_scale(const RT& m, const RT& n)
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{ int d = dimension();
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copy_on_write();
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entry(d) *= n;
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for (int i = 0; i < d; i++) entry(i) *= m;
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}
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VectorHd<RT,LA>& operator*=(const RT& n)
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/*{\Mbinop multiplies all Cartesian coordinates by |n|.}*/
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{ self_scale(n,1); return *this; }
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VectorHd<RT,LA>& operator*=(int n)
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{ self_scale(n,1); return *this; }
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VectorHd<RT,LA>& operator*=(const Quotient<RT>& r)
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/*{\Mbinop multiplies all Cartesian coordinates by |r|.}*/
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{ self_scale(r.numerator(),r.denominator()); return *this; }
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VectorHd<RT,LA> operator/(int n) const
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{ return scale(1,n); }
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VectorHd<RT,LA> operator/(const RT& n) const
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/*{\Mbinop returns the vector with Cartesian coordinates
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$v_i/n, 0 \leq i < d$.}*/
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{ return scale(1,n); }
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VectorHd<RT,LA> operator/(const Quotient<RT>& r) const
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/*{\Mbinop returns the vector with Cartesian coordinates
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$v_i/r, 0 \leq i < d$.}*/
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{ return scale(r.denominator(),r.numerator()); }
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VectorHd<RT,LA>& operator/=(const RT& n)
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{ self_scale(1,n); return *this; }
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/*{\Mbinop divides all Cartesian coordinates by |n|.}*/
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VectorHd<RT,LA>& operator/=(int n)
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{ self_scale(1,n); return *this; }
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VectorHd<RT,LA>& operator/=(const Quotient<RT>& r)
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{ self_scale(r.denominator(),r.numerator()); return *this; }
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/*{\Mbinop divides all Cartesian coordinates by |r|.}*/
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Quotient<RT>
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operator* (const VectorHd<RT,LA>& w) const
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/*{\Mbinop inner product, i.e., $\sum_{ 0 \le i < d } v_i w_i$,
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where $v_i$ and $w_i$ are the Cartesian coordinates of $v$ and $w$
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respectively. }*/
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{ int d = dimension();
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CGAL_assertion_msg((d==w.dimension()),
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"inner product: dimensions disagree.");
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RT nom = 0;
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for (int i = 0; i < d; i++)
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nom += homogeneous(i) * w.homogeneous(i);
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RT denom = homogeneous(d) * w.homogeneous(d);
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return Quotient<RT>(nom,denom);
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}
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VectorHd<RT,LA> operator+(const VectorHd<RT,LA>& w) const
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/*{\Mbinop returns the vector with Cartesian coordinates
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$v_i+w_i, 0 \leq i < d$.}*/
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{ VectorHd<RT,LA> res(dimension());
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res.ptr()->homogeneous_add(ptr(), w.ptr());
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return res;
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}
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VectorHd<RT,LA>& operator+=(const VectorHd<RT,LA>& w)
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/*{\Mbinop addition plus assignment.}*/
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{ int d = dimension();
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VectorHd<RT,LA> old(*this);
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*this = VectorHd<RT,LA>(d);
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ptr()->homogeneous_add(old.ptr(), w.ptr());
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return *this;
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}
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VectorHd<RT,LA> operator-(const VectorHd<RT,LA>& w) const
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/*{\Mbinop returns the vector with Cartesian coordinates
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$v_i-w_i, 0 \leq i < d$.}*/
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{ VectorHd<RT,LA> res(dimension());
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res.ptr()->homogeneous_sub(ptr(), w.ptr());
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return res;
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}
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VectorHd<RT,LA>& operator-=(const VectorHd<RT,LA>& w)
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/*{\Mbinop subtraction plus assignment.}*/
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{ int d = dimension();
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VectorHd<RT,LA> old(*this);
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*this = VectorHd<RT,LA>(d);
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ptr()->homogeneous_sub(old.ptr(), w.ptr());
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return *this;
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}
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VectorHd<RT,LA> operator-() const
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/*{\Munop returns the vector in opposite direction.}*/
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{ VectorHd<RT,LA> result(*this);
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result.copy_on_write(); // creates a copied object!
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result.ptr()->invert(dimension());
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return result;
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}
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static Comparison_result cmp(
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const VectorHd<RT,LA>& x, const VectorHd<RT,LA>& y)
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{ Compare_homogeneously<RT,LA> cmpobj;
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return cmpobj(x.vector_rep(),y.vector_rep());
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}
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bool operator==(const VectorHd<RT,LA>& w) const
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{ if ( this->identical(w) ) return true;
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if ( dimension() != w.dimension() ) return false;
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return cmp(*this,w) == EQUAL;
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}
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bool operator!=(const VectorHd<RT,LA>& w) const
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{ return !operator==(w); }
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bool is_zero() const
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/*{\Mop returns true if |\Mvar| is the zero vector. }*/
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{ for (int i = 0; i < dimension(); i++)
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if ( homogeneous(i) != RT(0) ) return false;
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return true;
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}
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/*{\Mtext \headerline{Downward compatibility}
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We provide all operations of the lower dimensional interface |x()|, |y()|,
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|z()|, |hx()|, |hy()|, |hz()|, |hw()|.}*/
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RT hx() const { return homogeneous(0); }
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RT hy() const { return homogeneous(1); }
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RT hz() const { return homogeneous(2); }
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RT hw() const { return homogeneous(dimension()); }
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Quotient<RT> x() const { return Quotient<RT>(hx(),hw());}
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Quotient<RT> y() const { return Quotient<RT>(hy(),hw());}
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Quotient<RT> z() const { return Quotient<RT>(hz(),hw());}
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friend std::istream& operator>> <>
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(std::istream& I, VectorHd<RT,LA>& v);
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friend std::ostream& operator<< <>
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(std::ostream& O, const VectorHd<RT,LA>& v);
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}; // end of class VectorHd
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template <class RT, class LA>
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VectorHd<RT,LA> operator*(const int& n, const VectorHd<RT,LA>& v)
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{ return v.scale(n,1); }
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template <class RT, class LA>
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VectorHd<RT,LA> operator*(const RT& n, const VectorHd<RT,LA>& v)
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/*{\Mbinopfunc returns the vector with Cartesian coordinates $n v_i$.}*/
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{ return v.scale(n,1); }
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template <class RT, class LA>
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VectorHd<RT,LA> operator*(const Quotient<RT>& r, const VectorHd<RT,LA>& v)
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/*{\Mbinopfunc returns the vector with Cartesian coordinates
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$r v_i, 0 \leq i < d$.}*/
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{ return v.scale(r.numerator(),r.denominator()); }
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/*{\Mimplementation
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|
Vectors are implemented by arrays of variables of type |RT|. All
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operations like creation, initialization, tests, vector arithmetic,
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input and output on a vector $v$ take time $O(|v.dimension()|)$.
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|
coordinate access, |dimension()| and conversions
|
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|
take constant time. The space requirement of a vector is
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|
$O(|v.dimension()|)$.}*/
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#undef PointHd
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} //namespace CGAL
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#endif // CGAL_VECTORHD_H
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//----------------------- end of file ----------------------------------
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