mirror of
https://github.com/vale981/arb
synced 2025-03-05 09:21:38 -05:00
124 lines
2.9 KiB
C
124 lines
2.9 KiB
C
/*
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Copyright (C) 2011 William Hart
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Copyright (C) 2012, 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 "arb_poly.h"
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/* TODO: tighten this code */
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void
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_arb_poly_div(arb_ptr Q,
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arb_srcptr A, slong lenA,
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arb_srcptr B, slong lenB, slong prec)
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{
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slong lenQ, lenB2;
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arb_ptr Arev, Brev;
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lenQ = lenA - lenB + 1;
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Arev = _arb_vec_init(2 * lenQ);
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Brev = Arev + lenQ;
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_arb_poly_reverse(Arev, A + (lenA - lenQ), lenQ, lenQ);
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if (lenB >= lenQ)
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{
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_arb_poly_reverse(Brev, B + (lenB - lenQ), lenQ, lenQ);
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lenB2 = lenQ;
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}
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else
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{
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_arb_poly_reverse(Brev, B, lenB, lenB);
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lenB2 = lenB;
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}
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_arb_poly_div_series(Q, Arev, lenQ, Brev, lenB2, lenQ, prec);
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_arb_poly_reverse(Q, Q, lenQ, lenQ);
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_arb_vec_clear(Arev, 2 * lenQ);
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}
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void _arb_poly_divrem(arb_ptr Q, arb_ptr R,
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arb_srcptr A, slong lenA,
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arb_srcptr B, slong lenB, slong prec)
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{
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const slong lenQ = lenA - lenB + 1;
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_arb_poly_div(Q, A, lenA, B, lenB, prec);
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if (lenB > 1)
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{
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if (lenQ >= lenB - 1)
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_arb_poly_mullow(R, Q, lenQ, B, lenB - 1, lenB - 1, prec);
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else
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_arb_poly_mullow(R, B, lenB - 1, Q, lenQ, lenB - 1, prec);
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_arb_vec_sub(R, A, R, lenB - 1, prec);
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}
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}
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void _arb_poly_rem(arb_ptr R,
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arb_srcptr A, slong lenA,
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arb_srcptr B, slong lenB, slong prec)
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{
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const slong lenQ = lenA - lenB + 1;
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arb_ptr Q = _arb_vec_init(lenQ);
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_arb_poly_divrem(Q, R, A, lenA, B, lenB, prec);
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_arb_vec_clear(Q, lenQ);
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}
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int arb_poly_divrem(arb_poly_t Q, arb_poly_t R,
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const arb_poly_t A, const arb_poly_t B, slong prec)
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{
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const slong lenA = A->length, lenB = B->length;
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if (lenB == 0 || arb_contains_zero(B->coeffs + lenB - 1))
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{
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return 0;
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}
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if (lenA < lenB)
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{
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arb_poly_set(R, A);
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arb_poly_zero(Q);
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return 1;
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}
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if (Q == A || Q == B)
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{
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arb_poly_t T;
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arb_poly_init(T);
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arb_poly_divrem(T, R, A, B, prec);
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arb_poly_swap(Q, T);
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arb_poly_clear(T);
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return 1;
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}
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if (R == A || R == B)
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{
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arb_poly_t U;
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arb_poly_init(U);
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arb_poly_divrem(Q, U, A, B, prec);
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arb_poly_swap(R, U);
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arb_poly_clear(U);
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return 1;
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}
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arb_poly_fit_length(Q, lenA - lenB + 1);
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arb_poly_fit_length(R, lenB - 1);
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_arb_poly_divrem(Q->coeffs, R->coeffs, A->coeffs, lenA,
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B->coeffs, lenB, prec);
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_arb_poly_set_length(Q, lenA - lenB + 1);
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_arb_poly_set_length(R, lenB - 1);
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_arb_poly_normalise(R);
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return 1;
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}
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