/usr/include/eclib/isogs.h is in libec-dev 2013-01-01-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 | // isogs.h: declaration of class IsogenyClass and related functions
//////////////////////////////////////////////////////////////////////////
//
// Copyright 1990-2012 John Cremona
//
// This file is part of the mwrank package.
//
// mwrank is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2 of the License, or (at your
// option) any later version.
//
// mwrank 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 General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License
// along with mwrank; if not, write to the Free Software Foundation,
// Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
//
//////////////////////////////////////////////////////////////////////////
#ifndef _ISOGS_H_
#define _ISOGS_H_
#include "cperiods.h" // which itself includes everything relevant
// isogeny functions:
vector<CurveRed> twoisog(const CurveRed& CR, int verbose);
vector<CurveRed> threeisog(const CurveRed& CR, int verbose);
vector<CurveRed> lisog(const CurveRed& CR, Cperiods& cp,
long ell, int verbose=0);
// cp must be normalized for lattice at call time
// returned array is of length up to 3
// of curves ell-isogenous to CR
int semistable(const CurveRed& CR);
vector<long> getelllist(const CurveRed& CR);
// returns list of possible primes l ("ell") for which CR might have an l-isogeny.
#define MAXNCURVES 26 // max number of curves in an isogeny class.
class IsogenyClass {
private:
vector<CurveRed> curves;
vector<long> llist;
long nell, ncurves, ndone;
int ss, verb;
Cperiods cp;
vector<long> fromlist; // fromlist[i]=j if curve i first constructed from
vector<long> isoglist; // curve j via an isoglist[i]-isogeny
vector<long> matij;
void matset(long i, long j, long ell) { matij[i*MAXNCURVES+j]=ell;}
void process(long i); // process i'th curve
public:
IsogenyClass(const CurveRed& C, int verbose);
void grow(void); // does the work
void display_llist(ostream& os)const {os<<llist;}
void displaycurves(ostream& os)const;
void displaymat(ostream& os)const;
void display(ostream& os)const {displaycurves(cout); displaymat(cout);}
void dumpdata(ostream& os, long rank); // output for textab to input
vector<long> getmat() const;
mat getmatrix() const;
long mat_entry(long i, long j)const {return matij[i*MAXNCURVES+j];}
vector<CurveRed> getcurves() const {return curves;}
};
#endif
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