arb/arb_poly/sin_cos_series_basecase.c
2015-02-10 17:45:20 +01:00

109 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) 2013 Fredrik Johansson
******************************************************************************/
#include "arb_poly.h"
void
_arb_poly_sin_cos_series_basecase(arb_ptr s, arb_ptr c, arb_srcptr h, long hlen,
long n, long prec, int times_pi)
{
long j, k, alen = FLINT_MIN(n, hlen);
arb_ptr a;
arb_t t, u;
if (times_pi)
arb_sin_cos_pi(s, c, h, prec);
else
arb_sin_cos(s, c, h, prec);
if (hlen == 1)
{
_arb_vec_zero(s + 1, n - 1);
_arb_vec_zero(c + 1, n - 1);
return;
}
arb_init(t);
arb_init(u);
a = _arb_vec_init(alen);
for (k = 1; k < alen; k++)
arb_mul_ui(a + k, h + k, k, prec);
if (times_pi)
{
arb_const_pi(t, prec);
_arb_vec_scalar_mul(a + 1, a + 1, alen - 1, t, prec);
}
for (k = 1; k < n; k++)
{
arb_zero(t);
arb_zero(u);
for (j = 1; j < FLINT_MIN(k + 1, hlen); j++)
{
arb_submul(t, a + j, s + k - j, prec);
arb_addmul(u, a + j, c + k - j, prec);
}
arb_div_ui(c + k, t, k, prec);
arb_div_ui(s + k, u, k, prec);
}
arb_clear(t);
arb_clear(u);
_arb_vec_clear(a, alen);
}
void
arb_poly_sin_cos_series_basecase(arb_poly_t s, arb_poly_t c,
const arb_poly_t h, long n, long prec, int times_pi)
{
long hlen = h->length;
if (n == 0)
{
arb_poly_zero(s);
arb_poly_zero(c);
return;
}
if (hlen == 0)
{
arb_poly_zero(s);
arb_poly_one(c);
return;
}
arb_poly_fit_length(s, n);
arb_poly_fit_length(c, n);
_arb_poly_sin_cos_series_basecase(s->coeffs, c->coeffs, h->coeffs, hlen, n, prec, times_pi);
_arb_poly_set_length(s, n);
_arb_poly_normalise(s);
_arb_poly_set_length(c, n);
_arb_poly_normalise(c);
}