/usr/include/CGAL/RS/ugcd/pp.h is in libcgal-dev 4.2-5ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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//
// 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__PP_H
#define CGAL_RS__PP_H
#include <gmp.h>
#include "p.h"
#include "pagealloc.h"
#include <cstdio>
namespace CGAL{
namespace RS_MGCD{
class Prime_polynomial:public Prime,public Page_alloc{
protected:
static
int pp_from_poly(CGALRS_PN *pp,mpz_t *poly,int n){
int i;
if(!(pp[n]=mpz_fdiv_ui(poly[n],p_prime())))
return -1;
for(i=0;i<n;++i)
pp[i]=mpz_fdiv_ui(poly[i],p_prime());
return n;
};
static
void pp_out_str(FILE *stream,CGALRS_PN* pp,int n){
int i;
for(i=n;i;--i)
fprintf(stream,"%d*x^%d+",pp[i],i);
fprintf(stream,"%d",pp[0]);
return;
};
// Knuth 2; m>=n
static
int pp_pdivrem(CGALRS_PN *r,CGALRS_PN *u,int m,CGALRS_PN *v,int n){
int k,j;
for(k=0;k<=m;++k)
r[k]=u[k];
// division p. 402
//for(k=m-n;k>=0;--k)
// for(j=n+k-1;j>=k;--j)
// r[j]=p_sub(r[j],p_mul(qk,v[j-k]));
// pseudo-division, p. 407
for(k=m-n;k>=0;--k)
for(j=n+k-1;j>=0;--j)
//r[j]=p_sub(
// p_mul(v[n],r[j]),
// p_mul(r[n+k],(j<k?0:v[j-k])));
r[j]=p_submuls(v[n],r[j],r[n+k],(j<k?0:v[j-k]));
--n;
while(!r[n]&&n)
--n;
return n;
};
static
CGALRS_PN pp_pp(CGALRS_PN *pp,CGALRS_PN *p,int dp){
int i;
CGALRS_PN inv,cont=p[dp];
for(i=0;i<dp;++i)
cont=p_gcd(cont,p[i]);
inv=p_inv(cont);
for(i=0;i<=dp;++i)
pp[i]=p_mul(p[i],inv);
return cont;
};
// GCL, page 280; da>=db
static
int pp_gcd(CGALRS_PN *g,CGALRS_PN *a,int da,CGALRS_PN *b,int db){
CGALRS_PN *r0,*r1,*r2;
int i,d0,d1,d2;
d0=da;
r0=(CGALRS_PN*)palloc((1+da)*sizeof(CGALRS_PN));
//for(i=0;i<=da;++i)
// r0[i]=a[i];
pp_pp(r0,a,da);
d1=db;
r1=(CGALRS_PN*)palloc((1+da)*sizeof(CGALRS_PN));
//for(i=0;i<=db;++i)
// r1[i]=b[i];
pp_pp(r1,b,db);
r2=(CGALRS_PN*)palloc((1+da)*sizeof(CGALRS_PN));
d2=pp_pdivrem(r2,r0,d0,r1,d1);
while(d2){
for(i=0;i<=d1;++i)
r0[i]=r1[i];
d0=d1;
//for(i=0;i<=d2;++i)
// r1[i]=r2[i];
pp_pp(r1,r2,d2);
d1=d2;
d2=pp_pdivrem(r2,r0,d0,r1,d1);
}
if(!r2[0]){
//CGALRS_PN inv=p_inv(r1[d1]);
//g[d1]=1;
//for(i=0;i<d1;++i)
// g[i]=p_mul(inv,r1[i]);
for(i=0;i<=d1;++i)
g[i]=r1[i];
}else{
d1=0;
g[0]=1;
}
CGALRS_PFREE(r0);
CGALRS_PFREE(r1);
CGALRS_PFREE(r2);
return d1;
};
}; // class Prime_polynomial
} // namespace RS_MGCD
} // namespace CGAL
#endif // CGAL_RS__PP_H
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