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https://github.com/vale981/arb
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63 lines
1.4 KiB
C
63 lines
1.4 KiB
C
/*
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Copyright (C) 2012 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 "acb_mat.h"
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void
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acb_mat_pow_ui(acb_mat_t B, const acb_mat_t A, ulong exp, slong prec)
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{
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slong d = acb_mat_nrows(A);
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if (exp <= 2 || d <= 1)
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{
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if (exp == 0 || d == 0)
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{
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acb_mat_one(B);
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}
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else if (d == 1)
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{
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acb_pow_ui(acb_mat_entry(B, 0, 0),
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acb_mat_entry(A, 0, 0), exp, prec);
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}
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else if (exp == 1)
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{
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acb_mat_set(B, A);
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}
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else if (exp == 2)
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{
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acb_mat_sqr(B, A, prec);
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}
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}
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else
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{
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acb_mat_t T, U;
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slong i;
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acb_mat_init(T, d, d);
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acb_mat_set(T, A);
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acb_mat_init(U, d, d);
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for (i = ((slong) FLINT_BIT_COUNT(exp)) - 2; i >= 0; i--)
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{
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acb_mat_sqr(U, T, prec);
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if (exp & (WORD(1) << i))
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acb_mat_mul(T, U, A, prec);
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else
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acb_mat_swap(T, U);
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}
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acb_mat_swap(B, T);
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acb_mat_clear(T);
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acb_mat_clear(U);
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}
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}
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