mirror of
https://github.com/vale981/arb
synced 2025-03-05 09:21:38 -05:00
112 lines
2.5 KiB
C
112 lines
2.5 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) 2014 Fredrik Johansson
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******************************************************************************/
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#include "acb_modular.h"
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static int
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fmpz_kronecker(const fmpz_t a, const fmpz_t b)
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{
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if (fmpz_sgn(b) < 0)
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{
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int r;
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fmpz_t t;
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fmpz_init(t);
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fmpz_neg(t, b);
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r = fmpz_kronecker(a, t);
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fmpz_clear(t);
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return r;
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}
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else if (fmpz_is_one(b))
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{
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return 1;
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}
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else
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{
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return fmpz_jacobi(a, b);
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}
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}
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int
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acb_modular_epsilon_arg(const psl2z_t g)
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{
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#define a (&g->a)
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#define b (&g->b)
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#define c (&g->c)
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#define d (&g->d)
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if (fmpz_is_zero(c))
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{
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return fmpz_fdiv_ui(b, 24);
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}
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else
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{
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int aa, bb, cc, dd;
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int u;
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aa = fmpz_fdiv_ui(a, 24);
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bb = fmpz_fdiv_ui(b, 24);
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cc = fmpz_fdiv_ui(c, 24);
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dd = fmpz_fdiv_ui(d, 24);
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if (cc % 2 == 1)
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{
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u = fmpz_kronecker(a, c);
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aa = aa*bb + 2*aa*cc - 3*cc + cc*dd*(1-aa*aa);
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}
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else
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{
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u = fmpz_kronecker(c, a);
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aa = aa*bb - aa*cc + 3*aa - 3 + cc*dd*(1-aa*aa);
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}
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if (u == -1)
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{
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aa += 12;
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}
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else if (u != 1)
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{
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printf("bad kronecker input\n");
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abort();
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}
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/* mod 24 */
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if (aa < 0)
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{
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aa = 24 - ((-aa) % 24);
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if (aa == 24)
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aa = 0;
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}
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else
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aa = aa % 24;
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return aa;
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}
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#undef a
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#undef b
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#undef c
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#undef d
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}
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