mirror of
https://github.com/vale981/arb
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50 lines
1.1 KiB
C
50 lines
1.1 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 "bernoulli.h"
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#include "arb.h"
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void
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_bernoulli_fmpq_ui_zeta(fmpz_t num, fmpz_t den, ulong n)
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{
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slong prec;
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arb_t t;
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arith_bernoulli_number_denom(den, n);
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if (n % 2)
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{
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fmpz_set_si(num, -(n == 1));
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return;
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}
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if (n < BERNOULLI_SMALL_NUMER_LIMIT)
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{
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fmpz_set_si(num, _bernoulli_numer_small[n / 2]);
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return;
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}
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arb_init(t);
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for (prec = arith_bernoulli_number_size(n) + fmpz_bits(den) + 2; ; prec += 20)
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{
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arb_bernoulli_ui_zeta(t, n, prec);
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arb_mul_fmpz(t, t, den, prec);
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if (arb_get_unique_fmpz(num, t))
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break;
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flint_printf("warning: %wd insufficient precision for Bernoulli number %wu\n", prec, n);
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}
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arb_clear(t);
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}
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