mirror of
https://github.com/vale981/arb
synced 2025-03-05 17:31:38 -05:00
131 lines
3.5 KiB
C
131 lines
3.5 KiB
C
/*=============================================================================
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This file is part of FLINT.
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FLINT 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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FLINT 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 FLINT; 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) 2012 Fredrik Johansson
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******************************************************************************/
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#include "arb_poly.h"
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/* z = x + y/2^shift, assumes lengths > 0, shift >= 0 */
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void
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_arb_poly_add_shift(fmpz * z, fmpz_t zrad,
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const fmpz * x, long xlen, const fmpz_t xrad,
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const fmpz * y, long ylen, const fmpz_t yrad, long shift)
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{
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fmpz_t t;
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long i;
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fmpz_init(t);
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if (xlen >= ylen)
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{
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for (i = 0; i < ylen; i++)
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{
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fmpz_tdiv_q_2exp(t, y + i, shift);
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fmpz_add(z + i, x + i, t);
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}
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for (i = ylen; i < xlen; i++)
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fmpz_set(z + i, x + i);
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}
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else
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{
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for (i = 0; i < xlen; i++)
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{
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fmpz_tdiv_q_2exp(t, y + i, shift);
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fmpz_add(z + i, x + i, t);
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}
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for (i = xlen; i < ylen; i++)
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fmpz_tdiv_q_2exp(z + i, y + i, shift);
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}
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fmpz_cdiv_q_2exp(t, yrad, shift);
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fmpz_add(zrad, xrad, t);
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fmpz_add_ui(zrad, zrad, 1UL);
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fmpz_clear(t);
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}
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void
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arb_poly_add(arb_poly_t z, const arb_poly_t x, const arb_poly_t y)
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{
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long xlen, ylen, zlen;
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fmpz *zp, *xp, *yp;
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xlen = x->length;
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ylen = y->length;
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if (xlen == 0)
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{
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arb_poly_set(z, y);
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return;
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}
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if (ylen == 0)
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{
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arb_poly_set(z, x);
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return;
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}
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zlen = FLINT_MAX(xlen, ylen);
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_arb_poly_fit_length(z, zlen);
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zp = arb_poly_coeffs(z);
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xp = arb_poly_coeffs(x);
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yp = arb_poly_coeffs(y);
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if (fmpz_equal(arb_poly_expref(x), arb_poly_expref(y)))
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{
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_fmpz_poly_add(zp, xp, xlen, yp, ylen);
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fmpz_set(arb_poly_expref(z), arb_poly_expref(x));
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fmpz_add(arb_poly_radref(z), arb_poly_radref(x), arb_poly_radref(y));
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}
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else
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{
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/* TODO: handle huge exponents */
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/* TODO: be smart when one poly is exact */
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/* TODO: aliasing? */
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long shift;
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shift = fmpz_get_si(arb_poly_expref(x)) -
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fmpz_get_si(arb_poly_expref(y));
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if (shift > 0)
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{
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fmpz_set(arb_poly_expref(z), arb_poly_expref(x));
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_arb_poly_add_shift(zp, arb_poly_radref(z),
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xp, xlen, arb_poly_radref(x),
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yp, ylen, arb_poly_radref(y), shift);
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}
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else
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{
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fmpz_set(arb_poly_expref(z), arb_poly_expref(y));
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_arb_poly_add_shift(zp, arb_poly_radref(z),
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yp, ylen, arb_poly_radref(y),
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xp, xlen, arb_poly_radref(x), -shift);
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}
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}
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z->length = zlen;
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}
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