arb/fmprb/sin_cos.c

290 lines
7.4 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, 2013 Fredrik Johansson
******************************************************************************/
#include "fmprb.h"
#define MAGLIM(prec) FLINT_MAX(65536, (4*prec))
static long
_fmpr_sin(fmpr_t y, const fmpr_t x, long prec, fmpr_rnd_t rnd)
{
long r;
CALL_MPFR_FUNC(r, mpfr_sin, y, x, prec, rnd);
return r;
}
static long
_fmpr_cos(fmpr_t y, const fmpr_t x, long prec, fmpr_rnd_t rnd)
{
long r;
CALL_MPFR_FUNC(r, mpfr_cos, y, x, prec, rnd);
return r;
}
static void
_fmpr_sin_cos(long * r1, long * r2, fmpr_t s, fmpr_t c, const fmpr_t x, long prec, fmpr_rnd_t rnd)
{
CALL_MPFR_FUNC_2X1(*r1, *r2, mpfr_sin_cos, s, c, x, prec, rnd);
}
void
fmprb_sin_fmpr(fmprb_t s, const fmpr_t x, long prec, long maglim)
{
if (fmpr_is_special(x))
{
if (fmpr_is_zero(x))
{
fmprb_zero(s);
}
else if (fmpr_is_nan(x))
{
fmpr_nan(fmprb_midref(s));
fmpr_pos_inf(fmprb_radref(s));
}
else
{
fmpr_zero(fmprb_midref(s));
fmpr_one(fmprb_radref(s));
}
}
else
{
long r;
fmpz_t mag;
fmpz_init(mag);
/* 2^(mag-1) <= |x| < 2^mag */
fmpr_abs_bound_lt_2exp_fmpz(mag, x);
/* sin x = x + eps, |eps| < x^3 */
if (fmpz_cmp_si(mag, -(prec/3) - 2) < 0)
{
fmpz_mul_ui(mag, mag, 3);
fmprb_set_fmpr(s, x);
fmprb_set_round(s, s, prec);
fmprb_add_error_2exp_fmpz(s, mag);
}
/* huge */
else if (fmpz_cmp_si(mag, maglim) > 0)
{
fmpr_zero(fmprb_midref(s));
fmpr_one(fmprb_radref(s));
}
else
{
r = _fmpr_sin(fmprb_midref(s), x, prec, FMPR_RND_DOWN);
fmpr_set_error_result(fmprb_radref(s), fmprb_midref(s), r);
}
fmpz_clear(mag);
}
}
void
fmprb_cos_fmpr(fmprb_t c, const fmpr_t x, long prec, long maglim)
{
if (fmpr_is_special(x))
{
if (fmpr_is_zero(x))
{
fmprb_one(c);
}
else if (fmpr_is_nan(x))
{
fmpr_nan(fmprb_midref(c));
fmpr_pos_inf(fmprb_radref(c));
}
else
{
fmpr_zero(fmprb_midref(c));
fmpr_one(fmprb_radref(c));
}
}
else
{
long r;
fmpz_t mag;
fmpz_init(mag);
/* 2^(mag-1) <= |x| < 2^mag */
fmpr_abs_bound_lt_2exp_fmpz(mag, x);
/* cos x = 1 - eps, |eps| < x^2 */
if (fmpz_cmp_si(mag, -(prec/2) - 2) < 0)
{
fmpz_mul_ui(mag, mag, 2);
fmprb_one(c);
fmprb_add_error_2exp_fmpz(c, mag);
}
/* huge */
else if (fmpz_cmp_si(mag, maglim) > 0)
{
fmpr_zero(fmprb_midref(c));
fmpr_one(fmprb_radref(c));
}
else
{
r = _fmpr_cos(fmprb_midref(c), x, prec, FMPR_RND_DOWN);
fmpr_set_error_result(fmprb_radref(c), fmprb_midref(c), r);
}
fmpz_clear(mag);
}
}
void
fmprb_sin_cos_fmpr(fmprb_t s, fmprb_t c, const fmpr_t x, long prec, long maglim)
{
if (fmpr_is_special(x))
{
if (fmpr_is_zero(x))
{
fmprb_zero(s);
fmprb_one(c);
}
else if (fmpr_is_nan(x))
{
fmpr_nan(fmprb_midref(s));
fmpr_pos_inf(fmprb_radref(s));
fmprb_set(c, s);
}
else
{
fmpr_zero(fmprb_midref(s));
fmpr_one(fmprb_radref(s));
fmprb_set(c, s);
}
}
else
{
long r1, r2;
fmpz_t mag;
fmpz_init(mag);
/* 2^(mag-1) <= |x| < 2^mag */
fmpr_abs_bound_lt_2exp_fmpz(mag, x);
/* sin x = x + eps, |eps| < x^3 */
/* cos x = 1 - eps, |eps| < x^2 */
if (fmpz_cmp_si(mag, -(prec/2) - 2) < 0)
{
fmpz_mul_ui(mag, mag, 3);
fmprb_set_fmpr(s, x);
fmprb_set_round(s, s, prec);
fmprb_add_error_2exp_fmpz(s, mag);
fmpz_divexact_ui(mag, mag, 3);
fmpz_mul_ui(mag, mag, 2);
fmprb_one(c);
fmprb_add_error_2exp_fmpz(c, mag);
}
/* huge */
else if (fmpz_cmp_si(mag, maglim) > 0)
{
fmpr_zero(fmprb_midref(s));
fmpr_one(fmprb_radref(s));
fmprb_set(c, s);
}
else
{
_fmpr_sin_cos(&r1, &r2, fmprb_midref(s), fmprb_midref(c), x, prec, FMPR_RND_DOWN);
fmpr_set_error_result(fmprb_radref(s), fmprb_midref(s), r1);
fmpr_set_error_result(fmprb_radref(c), fmprb_midref(c), r2);
}
fmpz_clear(mag);
}
}
void
fmprb_sin(fmprb_t s, const fmprb_t x, long prec)
{
if (fmprb_is_exact(x))
{
fmprb_sin_fmpr(s, fmprb_midref(x), prec, MAGLIM(prec));
}
else
{
fmpr_t t;
fmpr_init(t);
if (fmpr_cmpabs_2exp_si(fmprb_radref(x), 1) > 0)
fmpr_set_si_2exp_si(t, 1, 1);
else
fmpr_set(t, fmprb_radref(x));
fmprb_sin_fmpr(s, fmprb_midref(x), prec, MAGLIM(prec));
fmpr_add(fmprb_radref(s), fmprb_radref(s), t, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_clear(t);
}
fmprb_adjust(s);
}
void
fmprb_cos(fmprb_t c, const fmprb_t x, long prec)
{
if (fmprb_is_exact(x))
{
fmprb_cos_fmpr(c, fmprb_midref(x), prec, MAGLIM(prec));
}
else
{
fmpr_t t;
fmpr_init(t);
if (fmpr_cmpabs_2exp_si(fmprb_radref(x), 1) > 0)
fmpr_set_si_2exp_si(t, 1, 1);
else
fmpr_set(t, fmprb_radref(x));
fmprb_cos_fmpr(c, fmprb_midref(x), prec, MAGLIM(prec));
fmpr_add(fmprb_radref(c), fmprb_radref(c), t, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_clear(t);
}
fmprb_adjust(c);
}
void
fmprb_sin_cos(fmprb_t s, fmprb_t c, const fmprb_t x, long prec)
{
if (fmprb_is_exact(x))
{
fmprb_sin_cos_fmpr(s, c, fmprb_midref(x), prec, MAGLIM(prec));
}
else
{
fmpr_t t;
fmpr_init(t);
if (fmpr_cmpabs_2exp_si(fmprb_radref(x), 1) > 0)
fmpr_set_si_2exp_si(t, 1, 1);
else
fmpr_set(t, fmprb_radref(x));
fmprb_sin_cos_fmpr(s, c, fmprb_midref(x), prec, MAGLIM(prec));
fmpr_add(fmprb_radref(s), fmprb_radref(s), t, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_add(fmprb_radref(c), fmprb_radref(c), t, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_clear(t);
}
fmprb_adjust(s);
fmprb_adjust(c);
}