mirror of
https://github.com/vale981/arb
synced 2025-03-06 09:51:39 -05:00
114 lines
3.1 KiB
C
114 lines
3.1 KiB
C
/*=============================================================================
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This file is part of ARB.
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ARB is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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ARB is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with ARB; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2012 Fredrik Johansson
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******************************************************************************/
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#include "fmpcb_poly.h"
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#define MUL_CUTOFF 24
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static void
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_fmpcb_poly_exp_series_basecase_rec(fmpcb_ptr f, fmpcb_ptr a,
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fmpcb_srcptr h, long hlen, long n, long prec)
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{
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long j, k;
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fmpcb_t s;
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fmpcb_init(s);
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fmpcb_exp(f, h, prec);
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for (k = 1; k < hlen; k++)
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fmpcb_mul_ui(a + k, h + k, k, prec);
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for (k = 1; k < n; k++)
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{
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fmpcb_zero(s);
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for (j = 1; j < FLINT_MIN(k + 1, hlen); j++)
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fmpcb_addmul(s, a + j, f + k - j, prec);
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fmpcb_div_ui(f + k, s, k, prec);
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}
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fmpcb_clear(s);
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}
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void
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_fmpcb_poly_exp_series_basecase(fmpcb_ptr f,
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fmpcb_srcptr h, long hlen, long n, long prec)
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{
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hlen = FLINT_MIN(n, hlen);
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if (n < MUL_CUTOFF || hlen < 0.9 * n)
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{
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fmpcb_ptr t = _fmpcb_vec_init(hlen);
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_fmpcb_poly_exp_series_basecase_rec(f, t, h, hlen, n, prec);
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_fmpcb_vec_clear(t, hlen);
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}
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else
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{
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long m, v;
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fmpcb_ptr t, u;
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m = (n + 2) / 3;
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v = m * 2;
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t = _fmpcb_vec_init(n);
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u = _fmpcb_vec_init(n - m);
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_fmpcb_poly_mullow(t, h + m, hlen - m, h + m, hlen - m, n - v, prec);
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_fmpcb_vec_scalar_mul_2exp_si(t, t, n - v, -1);
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_fmpcb_vec_set(u, h + m, v - m);
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_fmpcb_poly_add(u + v - m, t, n - v, h + v, hlen - v, prec);
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_fmpcb_poly_exp_series_basecase_rec(f, t, h, m, n, prec);
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_fmpcb_poly_mullow(t, f, n, u, n - m, n - m, prec);
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_fmpcb_poly_add(f + m, f + m, n - m, t, n - m, prec);
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_fmpcb_vec_clear(t, n);
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_fmpcb_vec_clear(u, n - m);
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}
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}
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void
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fmpcb_poly_exp_series_basecase(fmpcb_poly_t f, const fmpcb_poly_t h, long n, long prec)
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{
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long hlen = h->length;
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if (n == 0)
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{
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fmpcb_poly_zero(f);
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return;
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}
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if (hlen == 0)
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{
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fmpcb_poly_one(f);
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return;
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}
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fmpcb_poly_fit_length(f, n);
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_fmpcb_poly_exp_series_basecase(f->coeffs, h->coeffs, hlen, n, prec);
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_fmpcb_poly_set_length(f, n);
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_fmpcb_poly_normalise(f);
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}
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