mirror of
https://github.com/vale981/arb
synced 2025-03-06 09:51:39 -05:00
100 lines
2.9 KiB
C
100 lines
2.9 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 "fmprb_poly.h"
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void
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_fmprb_poly_log_series(fmprb_struct * res, fmprb_struct * f, long n, long prec)
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{
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/* log(c+f) = log(c*(1+f/c)) = log(c) + log(1+f/c) */
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if (!fmprb_is_one(f))
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{
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fmprb_struct * h;
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long i;
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h = _fmprb_vec_init(n);
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fmprb_one(h);
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for (i = 1; i < n; i++)
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fmprb_div(h + i, f + i, f, prec);
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_fmprb_poly_log_series(res, h, n, prec);
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fmprb_log(res, f, prec);
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_fmprb_vec_clear(h, n);
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}
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else
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{
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fmprb_struct * f_diff;
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fmprb_struct * f_inv;
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f_diff = _fmprb_vec_init(n);
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f_inv = _fmprb_vec_init(n);
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_fmprb_poly_derivative(f_diff, f, n, prec);
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fmprb_zero(f_diff + n - 1);
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_fmprb_poly_inv_series(f_inv, f, n, prec);
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_fmprb_poly_mullow(res, f_diff, n - 1, f_inv, n - 1, n - 1, prec);
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_fmprb_poly_integral(res, res, n, prec);
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_fmprb_vec_clear(f_diff, n);
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_fmprb_vec_clear(f_inv, n);
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}
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}
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void
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fmprb_poly_log_series(fmprb_poly_t res, const fmprb_poly_t f, long n, long prec)
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{
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if (f->length < 1 || n < 1)
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{
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printf("Exception: log_series: input must be nonzero\n");
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abort();
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}
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if (f->length < n || res == f)
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{
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long i;
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fmprb_poly_t t;
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fmprb_poly_init(t);
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fmprb_poly_fit_length(t, n);
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for (i = 0; i < FLINT_MIN(n, f->length); i++)
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fmprb_set(t->coeffs + i, f->coeffs + i);
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for (i = FLINT_MIN(n, f->length); i < n; i++)
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fmprb_zero(t->coeffs + i);
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_fmprb_poly_set_length(t, n);
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fmprb_poly_log_series(res, t, n, prec);
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fmprb_poly_clear(t);
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return;
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}
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fmprb_poly_fit_length(res, n);
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_fmprb_poly_log_series(res->coeffs, f->coeffs, n, prec);
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_fmprb_poly_set_length(res, n);
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_fmprb_poly_normalise(res);
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}
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