mirror of
https://github.com/vale981/arb
synced 2025-03-05 09:21:38 -05:00
94 lines
2.8 KiB
C
94 lines
2.8 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_poly.h"
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void
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_arb_poly_product_roots_complex(arb_ptr poly, arb_srcptr r, slong rn,
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acb_srcptr c, slong cn, slong prec)
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{
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if (rn == 0 && cn == 0)
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{
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arb_one(poly);
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}
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else if (rn == 1 && cn == 0)
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{
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arb_neg(poly, r);
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arb_one(poly + 1);
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}
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else if (rn == 2 && cn == 0)
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{
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arb_mul(poly, r + 0, r + 1, prec);
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arb_add(poly + 1, r + 0, r + 1, prec);
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arb_neg(poly + 1, poly + 1);
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arb_one(poly + 2);
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}
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else if (rn == 3 && cn == 0)
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{
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arb_mul(poly + 1, r, r + 1, prec);
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arb_mul(poly, poly + 1, r + 2, prec);
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arb_neg(poly, poly);
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arb_add(poly + 2, r, r + 1, prec);
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arb_addmul(poly + 1, poly + 2, r + 2, prec);
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arb_add(poly + 2, poly + 2, r + 2, prec);
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arb_neg(poly + 2, poly + 2);
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arb_one(poly + 3);
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}
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else if (rn == 0 && cn == 1)
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{
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arb_mul(poly, acb_realref(c), acb_realref(c), prec);
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arb_addmul(poly, acb_imagref(c), acb_imagref(c), prec);
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arb_mul_2exp_si(poly + 1, acb_realref(c), 1);
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arb_neg(poly + 1, poly + 1);
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arb_one(poly + 2);
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}
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else if (rn == 1 && cn == 1)
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{
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arb_mul(poly + 1, acb_realref(c), acb_realref(c), prec);
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arb_addmul(poly + 1, acb_imagref(c), acb_imagref(c), prec);
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arb_mul(poly, poly + 1, r, prec);
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arb_neg(poly, poly);
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arb_mul_2exp_si(poly + 2, acb_realref(c), 1);
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arb_addmul(poly + 1, poly + 2, r, prec);
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arb_add(poly + 2, poly + 2, r, prec);
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arb_neg(poly + 2, poly + 2);
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arb_one(poly + 3);
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}
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else
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{
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slong rm, cm, rm2, cm2;
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arb_ptr tmp, tmp2;
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rm = (rn + 1) / 2;
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cm = cn / 2;
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rm2 = rn - rm;
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cm2 = cn - cm;
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tmp = _arb_vec_init(rn + 2 * cn + 2);
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tmp2 = tmp + rm + (2 * cm) + 1;
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_arb_poly_product_roots_complex(tmp, r, rm, c, cm, prec);
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_arb_poly_product_roots_complex(tmp2, r + rm, rm2, c + cm, cm2, prec);
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_arb_poly_mul_monic(poly, tmp, rm + 2 * cm + 1, tmp2, rm2 + 2 * cm2 + 1, prec);
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_arb_vec_clear(tmp, rn + 2 * cn + 2);
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}
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}
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void
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arb_poly_product_roots_complex(arb_poly_t poly,
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arb_srcptr r, slong rn, acb_srcptr c, slong cn, slong prec)
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{
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arb_poly_fit_length(poly, rn + 2 * cn + 1);
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_arb_poly_product_roots_complex(poly->coeffs, r, rn, c, cn, prec);
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_arb_poly_set_length(poly, rn + 2 * cn + 1);
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}
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