Revision cc4814cbc080b465aebd3c9d2b1c7c41d851d7e2 authored by Clément Pernet on 14 October 2022, 15:01:33 UTC, committed by Clément Pernet on 14 October 2022, 15:01:33 UTC
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ffpack_minpoly.inl
/* ffpack/ffpack_minpoly.inl
* Copyright (C) 2005 Clement Pernet
*
* Written by Clement Pernet <Clement.Pernet@imag.fr>
*
*
* ========LICENCE========
* This file is part of the library FFLAS-FFPACK.
*
* FFLAS-FFPACK is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
* ========LICENCE========
*.
*/
#ifndef __FFLASFFPACK_ffpack_minpoly_INL
#define __FFLASFFPACK_ffpack_minpoly_INL
namespace FFPACK {
template <class Field, class Polynomial>
inline Polynomial&
MinPoly (const Field& F, Polynomial& minP, const size_t N,
typename Field::ConstElement_ptr A, const size_t lda){
typename Field::RandIter G (F);
return MinPoly(F, minP, N, A, lda, G);
}
template <class Field, class Polynomial, class RandIter>
inline Polynomial&
MinPoly (const Field& F, Polynomial& minP, const size_t N,
typename Field::ConstElement_ptr A, const size_t lda,
RandIter& G){
if (N==0){
minP.resize(1);
F.assign(minP[0],F.one);
return minP;
}
// Allocating a Krylov basis
typename Field::Element_ptr v = FFLAS::fflas_new(F, 1, N);
// Picking a non-zero random vector
NonZeroRandomMatrix (F, 1, N, v, N, G);
MatVecMinPoly (F, minP, N, A, lda, v, 1);
FFLAS::fflas_delete(v);
return minP;
}
template <class Field, class Polynomial>
inline Polynomial&
MatVecMinPoly (const Field& F, Polynomial& minP, const size_t N,
typename Field::ConstElement_ptr A, const size_t lda,
typename Field::ConstElement_ptr v, const size_t incv){
// Construct the Krylov matrix K and eliminate it online
typename Field::Element_ptr K = FFLAS::fflas_new(F, N+1, N);
const size_t ldk = N;
size_t * P = FFLAS::fflas_new<size_t>(N);
typename Field::Element_ptr u = FFLAS::fflas_new(F, 1, N);
FFLAS::fassign (F, N, v, incv, u, 1);
Protected::MatVecMinPoly(F, minP, N, A, lda, u, 1, K, ldk, P);
FFLAS::fflas_delete (u);
FFLAS::fflas_delete (P);
FFLAS::fflas_delete (K);
return minP;
}
namespace Protected {
template <class Field, class Polynomial>
inline Polynomial&
MatVecMinPoly (const Field& F, Polynomial& minP, const size_t N,
typename Field::ConstElement_ptr A, const size_t lda,
typename Field::Element_ptr v, const size_t incv,
typename Field::Element_ptr K, const size_t ldk,
size_t * P){
FFLAS::fassign (F, N, v, incv, K, 1);
// Construct the Krylov matrix K and eliminate it online
// LUP factorization on K, construct K on the fly
size_t k = Protected::LUdivine_construct (F, FFLAS::FflasUnit, N+1, N, A, lda, K, ldk, v, incv, P, true, FfpackDense);
minP.resize(k+1);
minP[k] = F.one;
// If minpoly is X
if (k==1 && F.isZero (*(K+ldk))){
minP[0] = F.zero;
return minP;
}
// Get the coefficients from the first linear dependency in K
typename Field::Element_ptr Kk = K+k*ldk;
ftrsv( F, FFLAS::FflasLower, FFLAS::FflasTrans, FFLAS::FflasNonUnit, k, K, ldk, Kk, 1);
for (size_t j=0; j<k; ++j)
F.neg (minP[j],Kk[j]);
return minP;
}
template <class Field, class Polynomial>
Polynomial&
Hybrid_KGF_LUK_MinPoly (const Field& F, Polynomial& minP, const size_t N
,typename Field::ConstElement_ptr A, const size_t lda
,typename Field::Element_ptr X, const size_t ldx
,size_t* P
,const FFPACK_MINPOLY_TAG MinTag// = FfpackDense
,const size_t kg_mc// =0
,const size_t kg_mb//=0
,const size_t kg_j //=0
)
{
// nRow is the number of row in the krylov base already computed
size_t j, k ;
//size_t nRow = 2;
typename Polynomial::iterator it;
typename Field::Element_ptr Xi, Ui;
typename Field::RandIter g (F);
bool KeepOn=true;
typename Field::Element_ptr U = FFLAS::fflas_new (F, N);
// Picking a non zero vector
do{
for (Ui=U, Xi = X; Ui<U+N; ++Ui, ++Xi){
g.random (*Ui);
*Xi = *Ui;
if (!F.isZero(*Ui))
KeepOn = false;
}
}while(KeepOn);
// nRow = 1;
// LUP factorization of the Krylov Base Matrix
k = Protected::LUdivine_construct (F, FFLAS::FflasUnit, N+1, N, A, lda, X, ldx, U, 1, P, true,
MinTag, kg_mc, kg_mb, kg_j);
//FFLAS::fflas_delete( U);
minP.resize(k+1);
minP[k] = F.one;
if ( (k==1) && F.isZero(*(X+ldx))){ // minpoly is X
FFLAS::fflas_delete (U);
for (size_t i=0; i<k; ++i)
minP[i] = F.zero;
return minP;
}
// U contains the k first coefs of the minpoly
//typename Field::Element_ptr m= FFLAS::fflas_new<elt>(k);
FFLAS::fassign( F, k, X+k*ldx, 1, U, 1);
ftrsv( F, FFLAS::FflasLower, FFLAS::FflasTrans, FFLAS::FflasNonUnit, k, X, ldx, U, 1);
it = minP.begin();
for (j=0; j<k; ++j, it++){
F.neg(*it, U[j]);
}
FFLAS::fflas_delete (U);
return minP;
}
} // Protected
} // FFPACK
#endif // __FFLASFFPACK_ffpack_minpoly_INL
/* -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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