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added partial substitutions

This commit is contained in:
Eric Berberich 2008-10-05 16:04:35 +00:00
parent 4df4bd8dc4
commit 0598d13364
1 changed files with 97 additions and 0 deletions
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97
Polynomial/include/CGAL/Polynomial/polynomial_functions.h
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@ -34,10 +34,16 @@
#define CGAL_POLYNOMIAL_FUNCTIONS_H
#include <CGAL/config.h>
#include <vector>
#include <CGAL/Polynomial.h>
CGAL_BEGIN_NAMESPACE
// leading coefficient
//////////////////////
namespace CGALi {
template <class NT>
@ -76,6 +82,97 @@ bool check_leadcoeff(const CGAL::Polynomial< CGAL::Polynomial< NT > > &p) {
return CGALi::_check_leadcoeff(0, p.degree(), p);
}
// partial substitutions
////////////////////////
/*!\brief substitute innermost variable
*
* The substituted number \e x may have a more general number type
* NTX than the coefficient type NT, provided there is an explicit
* conversion NTX(NT).
*/
template < class NT, class NTX >
typename CGAL::Polynomial< typename CGAL::Coercion_traits< NT, NTX >::Type >
substitute_x(CGAL::Polynomial< CGAL::Polynomial< NT > > p, const NTX& x) {
typedef CGAL::Polynomial_traits_d<
CGAL::Polynomial < CGAL::Polynomial< NT > > > PT_d;
const int d = PT_d::d;
CGAL_precondition(d >= 1);
typedef typename CGAL::Coercion_traits< CGAL::Polynomial< NT >,NTX > CT;
typedef typename CT::Type Coercion;
typedef typename CGAL::Coercion_traits< NT, NTX > CTi;
typedef typename CTi::Type Coercion_i;
typedef CGAL::Polynomial_traits_d< Coercion > PT_d1;
std::vector< Coercion > replacements;
replacements.push_back(typename CT::Cast()(x));
for (int i = 0; i < d-1; i++) {
Coercion repl(Coercion_i(0), Coercion_i(1));
typename PT_d1::Move move;
repl = move(repl, d-2,i);
replacements.push_back(repl);
}
typename PT_d::Substitute substitute;
Coercion sub =
substitute(p, replacements.begin(), replacements.end());
//typename PT_d::Get_coefficient coeff;
//Coercion ret = coeff(sub,0,d-1);
return sub;
}
/*!\brief substitute two innermost variables
*
* The substituted numbers \e x and \e y may have a more general number type
* NTX than the coefficient type NT, provided there is an explicit
* conversion NTX(NT).
*/
template <class NT, class NTX>
typename CGAL::Polynomial< typename CGAL::Coercion_traits< NT, NTX >::Type >
substitute_xy(
const CGAL::Polynomial< CGAL::Polynomial< CGAL::Polynomial< NT > > >& p,
const NTX& x, const NTX& y
) {
typedef CGAL::Polynomial_traits_d<
CGAL::Polynomial< CGAL::Polynomial < CGAL::Polynomial< NT > > > > PT_d;
const int d = PT_d::d;
CGAL_precondition(d >= 2);
typedef typename CGAL::Coercion_traits< CGAL::Polynomial< NT >, NTX > CT;
typedef typename CT::Type Coercion;
typedef typename CGAL::Coercion_traits< NT, NTX > CTi;
typedef typename CT::Type Coercion_i;
typedef CGAL::Polynomial_traits_d < Coercion > PT_dc;
std::vector< Coercion > replacements;
replacements.push_back(typename CT::Cast()(x));
replacements.push_back(typename CT::Cast()(y));
for (int i = 0; i < d-2; i++) {
Coercion repl(typename PT_dc::Coefficient_type(0),
typename PT_dc::Coefficient_type(1));
typename PT_dc::Move move;
repl = move(repl, d-3,i);
replacements.push_back(repl);
}
typename PT_d::Substitute substitute;
Coercion sub =
substitute(p, replacements.begin(), replacements.end());
return sub;
}
CGAL_END_NAMESPACE
#endif // CGAL_POLYNOMIAL_FUNCTIONS_H