97 lines
2.7 KiB
C
97 lines
2.7 KiB
C
/*=============================================================================
|
|
|
|
This file is part of FLINT.
|
|
|
|
FLINT 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.
|
|
|
|
FLINT 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 FLINT; if not, write to the Free Software
|
|
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
|
|
=============================================================================*/
|
|
/******************************************************************************
|
|
|
|
Copyright (C) 2010, 2011 Sebastian Pancratz
|
|
|
|
******************************************************************************/
|
|
|
|
#include "fmpz_poly_q.h"
|
|
|
|
void fmpz_poly_q_derivative(fmpz_poly_q_t rop, const fmpz_poly_q_t op)
|
|
{
|
|
fmpz_poly_t d, lhs, rhs;
|
|
|
|
if (fmpz_poly_q_is_zero(op))
|
|
{
|
|
fmpz_poly_q_zero(rop);
|
|
return;
|
|
}
|
|
|
|
if (fmpz_poly_length(op->den) == 1)
|
|
{
|
|
fmpz_poly_derivative(rop->num, op->num);
|
|
fmpz_poly_set(rop->den, op->den);
|
|
fmpz_poly_q_canonicalise(rop);
|
|
return;
|
|
}
|
|
|
|
fmpz_poly_init(d);
|
|
fmpz_poly_init(rhs);
|
|
|
|
fmpz_poly_derivative(rhs, op->den);
|
|
fmpz_poly_gcd(d, rhs, op->den);
|
|
if (!fmpz_poly_is_one(d))
|
|
fmpz_poly_div(rhs, rhs, d);
|
|
fmpz_poly_mul(rhs, op->num, rhs);
|
|
|
|
fmpz_poly_derivative(rop->num, op->num);
|
|
if (fmpz_poly_is_one(d))
|
|
{
|
|
fmpz_poly_mul(rop->num, rop->num, op->den);
|
|
fmpz_poly_pow(rop->den, op->den, 2);
|
|
}
|
|
else
|
|
{
|
|
fmpz_poly_init(lhs);
|
|
fmpz_poly_div(lhs, op->den, d);
|
|
fmpz_poly_mul(rop->num, rop->num, lhs);
|
|
fmpz_poly_mul(rop->den, op->den, lhs);
|
|
fmpz_poly_clear(lhs);
|
|
}
|
|
fmpz_poly_sub(rop->num, rop->num, rhs);
|
|
|
|
/* Canonicalise: there can be at most a constant factor */
|
|
{
|
|
fmpz_t a, b, c;
|
|
|
|
fmpz_init(a);
|
|
fmpz_init(b);
|
|
fmpz_init(c);
|
|
|
|
fmpz_poly_content(a, rop->num);
|
|
fmpz_poly_content(b, rop->den);
|
|
fmpz_gcd(c, a, b);
|
|
|
|
if (!fmpz_is_one(c))
|
|
{
|
|
fmpz_poly_scalar_divexact_fmpz(rop->num, rop->num, c);
|
|
fmpz_poly_scalar_divexact_fmpz(rop->den, rop->den, c);
|
|
}
|
|
|
|
fmpz_clear(a);
|
|
fmpz_clear(b);
|
|
fmpz_clear(c);
|
|
}
|
|
|
|
fmpz_poly_clear(d);
|
|
fmpz_poly_clear(rhs);
|
|
}
|