include/algebramix/p_expansion.hpp

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/******************************************************************************
* MODULE     : p_expansion.hpp
* DESCRIPTION: Expansions in base p
* COPYRIGHT  : (C) 2009  Gregoire Lecerf
*******************************************************************************
* This software falls under the GNU general public license and comes WITHOUT
* ANY WARRANTY WHATSOEVER. See the file $TEXMACS_PATH/LICENSE for more details.
* If you don't have this file, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
******************************************************************************/

#ifndef __MMX_P_EXPANSION_HPP
#define __MMX_P_EXPANSION_HPP
#include <numerix/modular.hpp>
#include <algebramix/polynomial.hpp>
#include <algebramix/polynomial_carry_naive.hpp>
#include <algebramix/base.hpp>

namespace mmx {

#define P_expansion_variant(M) Polynomial_carry_variant(M)
#define p_expansion(M,V) polynomial<M,V>
#define default_p_expansion(M) p_expansion(M,typename P_expansion_variant(M))
#define M modular<modulus<C,U1>,U2>

template<typename C,typename U1,typename U2,typename V>
struct as_helper<Lift_type (M), p_expansion (M,V) > {
  static Lift_type (M)
  cv (const p_expansion (M,V)& p) {
    typedef typename Base_transformer_unsigned(Lift_type (M),C) Baser;
    nat n= N(p);
    if (n == 0) return Lift_type (M) ();
    Baser baser (* get_modulus (p[0]));
    nat l= default_aligned_size<C> (n);
    C* c= mmx_new<C> (l);
    for (nat i= 0; i < N(p); i++) c[i]= * seg (p)[i];
    return inverse_base (vector<C> (c, n, l, get_format (*(p[0]))), baser); }
};

template<typename C,typename U1,typename U2,typename V>
struct as_helper<p_expansion (M,V), Lift_type (M)> {
  static p_expansion (M,V)
  cv (const Lift_type (M)& a) {
    typedef typename Base_transformer_unsigned(Lift_type (M),C) Baser;
    Baser baser (* M::get_modulus ());
    vector<C> x; direct_base (x, a, baser);  
    nat n= N(x), l= aligned_size<M,V> (N(x));
    M* c= mmx_new<M> (l);
    for (nat i= 0; i < n; i++) c[i]= M (x[i], true);
    format<M> fm; // FIXME: which format should be taken here?
    return p_expansion (M,V) (c, n, l, fm); }
};

template<typename C,typename U1,typename U2>
polynomial<M,typename polynomial_carry_variant_helper<M>::PV> 
as_p_expansion (const Lift_type (M)& a, const modulus<C,U1>& p) {
  typedef typename polynomial_carry_variant_helper<M>::PV V;
  typedef typename Base_transformer_unsigned(Lift_type (M),C) Baser;
  Baser baser (* p);
  M::set_modulus (p);
  vector<C> x; direct_base (x, a, baser);
  nat n= N(x), l= aligned_size<M,V> (N(x));
  M* c= mmx_new<M> (l);
  for (nat i= 0; i < n; i++) c[i]= M (x[i], true);
  format<M> fm; // FIXME: which format should be taken here?
  return polynomial<M,V> (c, n, l, fm);
}

#undef M

} // namespace mmx
#endif // __MMX_P_EXPANSION_HPP

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