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/**************************************************************************
* *
* Regina - A Normal Surface Theory Calculator *
* Computational Engine *
* *
* Copyright (c) 1999-2011, Ben Burton *
* For further details contact Ben Burton (bab@debian.org). *
* *
* This program is free software; you can redistribute it and/or *
* modify it under the terms of the GNU General Public License as *
* published by the Free Software Foundation; either version 2 of the *
* License, or (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, but *
* WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* General Public License for more details. *
* *
* You should have received a copy of the GNU General Public *
* License along with this program; if not, write to the Free *
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, *
* MA 02110-1301, USA. *
* *
**************************************************************************/
/* end stub */
/*! \file maths/nray.h
* \brief Provides a fast class for rational rays rooted at the origin.
*/
#ifndef __NRAY_H
#ifndef __DOXYGEN
#define __NRAY_H
#endif
#include "regina-core.h"
#include "maths/nlargeinteger.h"
#include "maths/nvector.h"
namespace regina {
/**
* \weakgroup maths
* @{
*/
/**
* A fast class for storing a ray rooted at the origin whose
* coordinates are rational. Such a ray is a half-line beginning at
* the origin and is represented by an integer point that it passes through.
* Positive scalar multiples of a ray are considered to represent the same ray.
*
* This class is intended for serious computation, and as a result it
* has a streamlined implementation with no virtual methods. It can be
* subclassed, but since there are no virtual methods, type information
* must generally be known at compile time. Nevertheless, in many respects,
* different subclasses of NRay can happily interact with one another.
*
* \warning As of Regina 4.90, this class merges the old functionality
* of NFastRay and NRay from Regina 4.6. Since functions are no longer
* virtual, the old clone() method and intersect() function are gone
* completely. Instead you can just use the copy constructor and standard
* linear operators respectively.
*
* \ifacespython Not present.
*/
class REGINA_API NRay : public NVector<NLargeInteger> {
public:
/**
* Creates a new ray all of whose coordinates are initialised to zero.
*
* @param length the number of elements in the new vector.
*/
NRay(unsigned length);
/**
* Creates a new ray that is a clone of the given ray.
*
* @param cloneMe the ray to clone.
*/
NRay(const NVector<NLargeInteger>& cloneMe);
/**
* Scales this vector down by the greatest common divisor of all
* its elements. The resulting vector will be the smallest
* multiple of the original that maintains integral entries, and
* these entries will have the same signs as the originals.
*
* This routine thus reduces a ray to its smallest possible
* representation.
*
* This routine poses no problem for vectors containing infinite
* elements; such elements are simply ignored and left at
* infinity.
*/
void scaleDown();
inline void negate();
};
/*@}*/
// Inline functions for NRay
inline NRay::NRay(unsigned length) : NVector<NLargeInteger>(length) {
// Don't bother passing zero to the parent constructor, since the
// default NLargeInteger constructor already sets elements to zero.
}
inline NRay::NRay(const NVector<NLargeInteger>& cloneMe) :
NVector<NLargeInteger>(cloneMe) {
}
inline void NRay::negate() {
// Slightly more efficient than the default implementation.
for (NLargeInteger* e = elements; e < end; ++e)
e->negate();
}
} // namespace regina
#endif
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