arb/fmpcb_poly/exp_series_basecase.c
2013-07-27 18:11:29 +02:00

78 lines
2.1 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 Fredrik Johansson
******************************************************************************/
#include "fmpcb_poly.h"
void
_fmpcb_poly_exp_series_basecase(fmpcb_ptr f,
fmpcb_srcptr h, long hlen, long n, long prec)
{
long j, k, alen = FLINT_MIN(n, hlen);
fmpcb_ptr a;
fmpcb_t s;
fmpcb_init(s);
a = _fmpcb_vec_init(alen);
fmpcb_exp(f, h, prec);
for (k = 1; k < alen; k++)
fmpcb_mul_ui(a + k, h + k, k, prec);
for (k = 1; k < n; k++)
{
fmpcb_zero(s);
for (j = 1; j < FLINT_MIN(k + 1, hlen); j++)
fmpcb_addmul(s, a + j, f + k - j, prec);
fmpcb_div_ui(f + k, s, k, prec);
}
fmpcb_clear(s);
_fmpcb_vec_clear(a, alen);
}
void
fmpcb_poly_exp_series_basecase(fmpcb_poly_t f, const fmpcb_poly_t h, long n, long prec)
{
long hlen = h->length;
if (n == 0)
{
fmpcb_poly_zero(f);
return;
}
if (hlen == 0)
{
fmpcb_poly_one(f);
return;
}
fmpcb_poly_fit_length(f, n);
_fmpcb_poly_exp_series_basecase(f->coeffs, h->coeffs, hlen, n, prec);
_fmpcb_poly_set_length(f, n);
_fmpcb_poly_normalise(f);
}