mirror of
https://github.com/vale981/arb
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105 lines
2.6 KiB
C
105 lines
2.6 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 "fmpr.h"
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slong
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fmpr_sqrt(fmpr_t y, const fmpr_t x, slong prec, fmpr_rnd_t rnd)
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{
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slong r;
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if (fmpr_is_special(x))
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{
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if (fmpr_is_zero(x))
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fmpr_zero(y);
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else if (fmpr_is_pos_inf(x))
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fmpr_pos_inf(y);
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else
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fmpr_nan(y);
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return FMPR_RESULT_EXACT;
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}
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if (fmpr_sgn(x) < 0)
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{
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fmpr_nan(y);
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return FMPR_RESULT_EXACT;
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}
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/* special case: 4^n */
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/* TODO: process all small exact square roots efficiently */
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if (fmpz_is_one(fmpr_manref(x)) && fmpz_is_even(fmpr_expref(x)))
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{
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r = fmpr_set_round(y, x, prec, rnd);
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fmpz_tdiv_q_2exp(fmpr_expref(y), fmpr_expref(y), 1);
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return r;
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}
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{
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fmpr_t t;
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fmpz_t e;
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fmpr_init(t);
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fmpz_init(e);
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fmpz_neg(e, fmpr_expref(x));
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if (fmpz_is_odd(e))
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fmpz_add_ui(e, e, 1);
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fmpr_mul_2exp_fmpz(t, x, e);
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CALL_MPFR_FUNC(r, mpfr_sqrt, y, t, prec, rnd);
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fmpz_neg(e, e);
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fmpz_tdiv_q_2exp(e, e, 1);
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fmpr_mul_2exp_fmpz(y, y, e);
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fmpr_clear(t);
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fmpz_clear(e);
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return r;
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}
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}
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slong
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fmpr_sqrt_ui(fmpr_t z, ulong x, slong prec, fmpr_rnd_t rnd)
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{
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fmpr_t t; slong r;
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fmpr_init(t);
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fmpr_set_ui(t, x);
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r = fmpr_sqrt(z, t, prec, rnd);
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fmpr_clear(t);
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return r;
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}
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slong
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fmpr_sqrt_fmpz(fmpr_t z, const fmpz_t x, slong prec, fmpr_rnd_t rnd)
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{
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fmpr_t t; slong r;
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fmpr_init(t);
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fmpr_set_fmpz(t, x);
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r = fmpr_sqrt(z, t, prec, rnd);
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fmpr_clear(t);
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return r;
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}
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