mirror of
https://github.com/vale981/arb
synced 2025-03-05 09:21:38 -05:00
100 lines
2.5 KiB
C
100 lines
2.5 KiB
C
/*
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Copyright (C) 2013 Fredrik Johansson
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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 it under
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the terms of the GNU Lesser General Public License (LGPL) as published
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by the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version. See <http://www.gnu.org/licenses/>.
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*/
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#include "acb_poly.h"
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void
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_acb_poly_sinh_cosh_series_exponential(acb_ptr s, acb_ptr c,
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const acb_srcptr h, slong hlen, slong len, slong prec)
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{
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acb_ptr t, u, v;
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acb_t s0, c0;
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hlen = FLINT_MIN(hlen, len);
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if (hlen == 1)
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{
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acb_sinh_cosh(s, c, h, prec);
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_acb_vec_zero(s + 1, len - 1);
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_acb_vec_zero(c + 1, len - 1);
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return;
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}
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acb_init(s0);
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acb_init(c0);
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t = _acb_vec_init(3 * len);
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u = t + len;
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v = u + len;
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acb_sinh_cosh(s0, c0, h, prec);
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_acb_vec_set(t + 1, h + 1, hlen - 1);
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_acb_poly_exp_series(t, t, len, len, prec);
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/* todo: part of the inverse could be avoided since exp computes
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it internally to half the length */
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_acb_poly_inv_series(u, t, len, len, prec);
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/* hyperbolic sine */
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_acb_vec_sub(s, t, u, len, prec);
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_acb_vec_scalar_mul_2exp_si(s, s, len, -1);
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/* hyperbolic cosine */
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_acb_vec_add(c, t, u, len, prec);
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_acb_vec_scalar_mul_2exp_si(c, c, len, -1);
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/* sinh(h0 + h1) = cosh(h0) sinh(h1) + sinh(h0) cosh(h1)
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cosh(h0 + h1) = cosh(h0) cosh(h1) + sinh(h0) sinh(h1) */
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if (!acb_is_zero(s0))
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{
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_acb_vec_scalar_mul(t, s, len, c0, prec);
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_acb_vec_scalar_mul(u, c, len, s0, prec);
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_acb_vec_scalar_mul(v, s, len, s0, prec);
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_acb_vec_add(s, t, u, len, prec);
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_acb_vec_scalar_mul(t, c, len, c0, prec);
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_acb_vec_add(c, t, v, len, prec);
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}
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_acb_vec_clear(t, 3 * len);
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acb_clear(s0);
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acb_clear(c0);
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}
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void
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acb_poly_sinh_cosh_series_exponential(acb_poly_t s, acb_poly_t c,
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const acb_poly_t h, slong n, slong prec)
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{
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slong hlen = h->length;
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if (n == 0)
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{
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acb_poly_zero(s);
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acb_poly_zero(c);
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return;
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}
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if (hlen == 0)
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{
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acb_poly_zero(s);
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acb_poly_one(c);
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return;
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}
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acb_poly_fit_length(s, n);
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acb_poly_fit_length(c, n);
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_acb_poly_sinh_cosh_series_exponential(s->coeffs, c->coeffs, h->coeffs, hlen, n, prec);
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_acb_poly_set_length(s, n);
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_acb_poly_normalise(s);
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_acb_poly_set_length(c, n);
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_acb_poly_normalise(c);
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}
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