mirror of
https://github.com/vale981/arb
synced 2025-03-06 01:41:39 -05:00
80 lines
2.3 KiB
C
80 lines
2.3 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) 2015 Fredrik Johansson
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******************************************************************************/
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#include "acb.h"
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slong
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acb_rel_error_bits(const acb_t x)
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{
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int am, ar, bm, br;
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slong result;
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const fmpz * radmag;
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const fmpz * midmag;
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fmpz_t t;
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am = !arf_is_zero(arb_midref(acb_realref(x)));
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ar = !mag_is_zero(arb_radref(acb_realref(x)));
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bm = !arf_is_zero(arb_midref(acb_imagref(x)));
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br = !mag_is_zero(arb_radref(acb_imagref(x)));
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/* no radius -- exact */
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if (!ar && !br)
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return -ARF_PREC_EXACT;
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/* no midpoint -- infinite relative error */
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if (!am && !bm)
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return ARF_PREC_EXACT;
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if (!acb_is_finite(x))
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return ARF_PREC_EXACT;
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#define ame ARF_EXPREF(arb_midref(acb_realref(x)))
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#define are MAG_EXPREF(arb_radref(acb_realref(x)))
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#define bme ARF_EXPREF(arb_midref(acb_imagref(x)))
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#define bre MAG_EXPREF(arb_radref(acb_imagref(x)))
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if (am && bm)
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midmag = fmpz_cmp(ame, bme) >= 0 ? ame : bme;
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else if (am)
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midmag = ame;
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else
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midmag = bme;
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if (ar && br)
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radmag = fmpz_cmp(are, bre) >= 0 ? are : bre;
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else if (ar)
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radmag = are;
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else
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radmag = bre;
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fmpz_init(t);
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fmpz_add_ui(t, radmag, 1);
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result = _fmpz_sub_small(t, midmag);
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fmpz_clear(t);
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return result;
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}
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