mirror of
https://github.com/vale981/arb
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55 lines
1.1 KiB
C
55 lines
1.1 KiB
C
/*
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Copyright (C) 2015 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 "mag.h"
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void
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mag_root(mag_t y, const mag_t x, ulong n)
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{
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if (n == 0)
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{
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mag_inf(y);
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}
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else if (n == 1 || mag_is_special(x))
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{
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mag_set(y, x);
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}
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else if (n == 2)
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{
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mag_sqrt(y, x);
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}
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else if (n == 4)
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{
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mag_sqrt(y, x);
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mag_sqrt(y, y);
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}
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else
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{
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fmpz_t e, f;
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fmpz_init_set_ui(e, MAG_BITS);
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fmpz_init(f);
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fmpz_sub(e, e, MAG_EXPREF(x));
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fmpz_cdiv_q_ui(e, e, n);
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fmpz_mul_ui(f, e, n);
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mag_mul_2exp_fmpz(y, x, f);
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mag_log1p(y, y);
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mag_div_ui(y, y, n);
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mag_exp(y, y);
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fmpz_neg(e, e);
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mag_mul_2exp_fmpz(y, y, e);
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fmpz_clear(e);
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fmpz_clear(f);
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}
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}
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