mirror of
https://github.com/vale981/arb
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42 lines
1 KiB
C
42 lines
1 KiB
C
/*
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Copyright (C) 2017 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 "arb_fmpz_poly.h"
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ulong arb_fmpz_poly_deflation(const fmpz_poly_t input)
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{
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slong i, coeff, deflation;
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if (input->length <= 1)
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return input->length;
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coeff = 1;
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while (fmpz_is_zero(input->coeffs + coeff))
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coeff++;
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deflation = n_gcd(input->length - 1, coeff);
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while ((deflation > 1) && (coeff + deflation < input->length))
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{
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for (i = 0; i < deflation - 1; i++)
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{
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coeff++;
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if (!fmpz_is_zero(input->coeffs + coeff))
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deflation = n_gcd(coeff, deflation);
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}
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if (i == deflation - 1)
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coeff++;
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}
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return deflation;
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}
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