mirror of
https://github.com/vale981/arb
synced 2025-03-05 09:21:38 -05:00
106 lines
2.8 KiB
C
106 lines
2.8 KiB
C
/*=============================================================================
|
|
|
|
This file is part of ARB.
|
|
|
|
ARB 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.
|
|
|
|
ARB 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 ARB; if not, write to the Free Software
|
|
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
|
|
=============================================================================*/
|
|
/******************************************************************************
|
|
|
|
Copyright (C) 2012, 2013 Fredrik Johansson
|
|
|
|
******************************************************************************/
|
|
|
|
#include "arb_poly.h"
|
|
|
|
#define MULLOW(z, x, xn, y, yn, nn, prec) \
|
|
if ((xn) >= (yn)) \
|
|
_arb_poly_mullow(z, x, xn, y, yn, nn, prec); \
|
|
else \
|
|
_arb_poly_mullow(z, y, yn, x, xn, nn, prec); \
|
|
|
|
void
|
|
_arb_poly_inv_series(arb_ptr Qinv,
|
|
arb_srcptr Q, slong Qlen, slong len, slong prec)
|
|
{
|
|
arb_inv(Qinv, Q, prec);
|
|
|
|
if (Qlen == 1)
|
|
{
|
|
_arb_vec_zero(Qinv + 1, len - 1);
|
|
}
|
|
else if (len == 2)
|
|
{
|
|
arb_div(Qinv + 1, Qinv, Q, prec);
|
|
arb_mul(Qinv + 1, Qinv + 1, Q + 1, prec);
|
|
arb_neg(Qinv + 1, Qinv + 1);
|
|
}
|
|
else
|
|
{
|
|
slong Qnlen, Wlen, W2len;
|
|
arb_ptr W;
|
|
|
|
W = _arb_vec_init(len);
|
|
|
|
NEWTON_INIT(1, len)
|
|
NEWTON_LOOP(m, n)
|
|
|
|
Qnlen = FLINT_MIN(Qlen, n);
|
|
Wlen = FLINT_MIN(Qnlen + m - 1, n);
|
|
W2len = Wlen - m;
|
|
MULLOW(W, Q, Qnlen, Qinv, m, Wlen, prec);
|
|
MULLOW(Qinv + m, Qinv, m, W + m, W2len, n - m, prec);
|
|
_arb_vec_neg(Qinv + m, Qinv + m, n - m);
|
|
|
|
NEWTON_END_LOOP
|
|
NEWTON_END
|
|
|
|
_arb_vec_clear(W, len);
|
|
}
|
|
}
|
|
|
|
void
|
|
arb_poly_inv_series(arb_poly_t Qinv, const arb_poly_t Q, slong n, slong prec)
|
|
{
|
|
if (n == 0)
|
|
{
|
|
arb_poly_zero(Qinv);
|
|
return;
|
|
}
|
|
|
|
if (Q->length == 0)
|
|
{
|
|
arb_poly_fit_length(Qinv, n);
|
|
_arb_vec_indeterminate(Qinv->coeffs, n);
|
|
_arb_poly_set_length(Qinv, n);
|
|
return;
|
|
}
|
|
|
|
if (Qinv == Q)
|
|
{
|
|
arb_poly_t t;
|
|
arb_poly_init(t);
|
|
arb_poly_inv_series(t, Q, n, prec);
|
|
arb_poly_swap(Qinv, t);
|
|
arb_poly_clear(t);
|
|
return;
|
|
}
|
|
|
|
arb_poly_fit_length(Qinv, n);
|
|
_arb_poly_inv_series(Qinv->coeffs, Q->coeffs, Q->length, n, prec);
|
|
_arb_poly_set_length(Qinv, n);
|
|
_arb_poly_normalise(Qinv);
|
|
}
|
|
|