/usr/include/CGAL/RS/ugcd/ugcd.h is in libcgal-dev 4.2-5ubuntu1.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 | // Copyright (c) 2007 Inria Lorraine (France). All rights reserved.
//
// This file is part of CGAL (www.cgal.org); 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 3 of the License,
// or (at your option) any later version.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL$
// $Id$
//
// Author: Luis Peñaranda <luis.penaranda@gmx.com>
#ifndef CGAL_RS__UGCD_H
#define CGAL_RS__UGCD_H
#include <gmp.h>
#include "primes.h"
// let's assume that 300 is enough for degree 500 gcds
#define CGALRS_MOD_QTY 300
namespace CGAL{
namespace RS_MGCD{
class Ugcd:public Primes{
public:
static int ugcd (mpz_t *gcd,mpz_t *Anp,int degA,mpz_t *Bnp,int degB){
mpz_t *A,*B;
mpz_t lcgcd,cA,cB;
mpz_ptr m,bound;
// dG is initialized to zero only to avoid compiler complaints
int dA,dB,dG=0,maxd,i,maxA,maxB;
size_t modsize,modalloc;
std::vector<CGALRS_PN* > p;
CGALRS_PN *mA,*mB,*mG,*mod;
CGALRS_PN lc=0,scaleG;
if(degB>degA){
if(!degA){
mpz_set_ui(gcd[0],1);
return 0;
}else
return ugcd(gcd,Bnp,degB,Anp,degA);
}
if(!degB){
mpz_set_ui(gcd[0],1);
return 0;
}
// initialize the memory
meminit();
A=(mpz_t*)malloc((1+degA)*sizeof(mpz_t));
B=(mpz_t*)malloc((1+degB)*sizeof(mpz_t));
mpz_init_set(cA,Anp[degA]);
for(i=0;i<degA;++i)
mpz_gcd(cA,cA,Anp[i]);
mpz_init_set(cB,Bnp[degB]);
for(i=0;i<degB;++i)
mpz_gcd(cB,cB,Bnp[i]);
for(i=0;i<=degA;++i){
mpz_init(A[i]);
mpz_divexact(A[i],Anp[i],cA);
}
for(i=0;i<=degB;++i){
mpz_init(B[i]);
mpz_divexact(B[i],Bnp[i],cB);
}
// calculate the gcd of the principal coefficients
mpz_init(lcgcd);
mpz_gcd(lcgcd,A[degA],B[degB]);
// find the limit of modular image computation
maxA=degA;
for(i=0;i<degA;++i)
if(mpz_cmpabs(A[i],A[maxA])>0)
maxA=i;
maxB=degB;
for(i=0;i<degB;++i)
if(mpz_cmpabs(B[i],B[maxB])>0)
maxB=i;
mpz_pow_ui(cA,A[maxA],2);
mpz_mul_ui(cA,cA,degA+1);
mpz_mul_2exp(cA,cA,2*degA);
mpz_sqrt(cA,cA);
mpz_pow_ui(cB,B[maxB],2);
mpz_mul_ui(cB,cB,degB+1);
mpz_mul_2exp(cB,cB,2*degB);
mpz_sqrt(cB,cB);
if(mpz_cmp(cA,cB)<0){
bound=(mpz_ptr)cA;
m=(mpz_ptr)cB;
}else{
bound=(mpz_ptr)cB;
m=(mpz_ptr)cA;
}
mpz_mul(bound,bound,lcgcd);
mpz_mul_2exp(bound,bound,1);
mpz_setbit(bound,0);
mA=(CGALRS_PN*)palloc((1+degA)*sizeof(CGALRS_PN));
mB=(CGALRS_PN*)palloc((1+degB)*sizeof(CGALRS_PN));
maxd=degA; // we know that degA>=degB
mG=(CGALRS_PN*)palloc((1+maxd)*sizeof(CGALRS_PN));
pr_init();
mpz_set_ui(m,1);
mod=(CGALRS_PN*)palloc(CGALRS_MOD_QTY*sizeof(CGALRS_PN));
modalloc=CGALRS_MOD_QTY;
modsize=0;
while(mpz_cmp(m,bound)<=0){
do{
p_set_prime(pr_next());
dA=pp_from_poly(mA,A,degA);
if(dA!=-1){
dB=pp_from_poly(mB,B,degB);
if(dB!=-1)
lc=mpz_fdiv_ui(lcgcd,p_prime());
// lc is the image of the principal coefficient
}
}while(dA==-1||dB==-1||!lc
||mpz_divisible_ui_p(A[degA],p_prime())
||mpz_divisible_ui_p(B[degB],p_prime()));
// now we calculate the gcd mod p_prime
dG=pp_gcd(mG,mA,degA,mB,degB);
scaleG=CGALRS_P_DIV(lc,mG[dG]);
mG[dG]=lc;
for(i=0;i<dG;++i)
mG[i]=p_mul(mG[i],scaleG);
if(!dG){ // done, we know that the gcd is constant
mpz_set_ui(gcd[0],1);
dG=0;
goto cleanandexit;
}
if(dG<maxd){
CGALRS_mpz_set_pn(m,p_prime());
maxd=dG;
p.clear();
p.push_back(mG);
mod[0]=p_prime();
modsize=1;
mG=(CGALRS_PN*)palloc((1+maxd)*sizeof(CGALRS_PN));
// TODO: clean the CGALRS_PN* that are in p
}else{
if(dG==maxd){
CGALRS_mpz_mul_pn(m,m,p_prime());
if(modsize==modalloc){
modalloc*=2;
mod=(CGALRS_PN*)
prealloc(mod,modalloc*sizeof(CGALRS_PN));
}
mod[modsize]=p_prime();
++modsize;
p.push_back(mG);
mG=(CGALRS_PN*)palloc((1+maxd)*sizeof(CGALRS_PN));
}
}
}
pcra(gcd,mod,p,maxd,modsize);
cleanandexit:
CGALRS_PFREE(mA);
CGALRS_PFREE(mB);
CGALRS_PFREE(mG);
CGALRS_PFREE(mod);
// TODO: clean the CGALRS_PN* that are in p
for(i=0;i<=degA;++i)
mpz_clear(A[i]);
for(i=0;i<=degB;++i)
mpz_clear(B[i]);
mpz_clear(m);
mpz_clear(bound);
mpz_clear(lcgcd);
free(A);
free(B);
memrelease();
return dG;
};
}; // class Ugcd
} // namespace RS_MGCD
} // namespace CGAL
#endif // CGAL_RS__UGCD_H
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