205 lines
6.4 KiB
C
205 lines
6.4 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 Sebastian Pancratz
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Copyright (C) 2013 Mike Hansen
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******************************************************************************/
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#ifdef T
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#include "templates.h"
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void
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_TEMPLATE(T, poly_compose_divconquer) (
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TEMPLATE(T, struct) * rop,
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const TEMPLATE(T, struct) * op1, slong len1,
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const TEMPLATE(T, struct) * op2, slong len2,
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const TEMPLATE(T, ctx_t) ctx)
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{
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slong i, j, k, n;
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slong *hlen, alloc, powlen;
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TEMPLATE(T, struct) * v, **h, *pow, *temp;
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if (len1 <= 2 || len2 <= 1)
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{
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if (len1 == 1)
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TEMPLATE(T, set) (rop, op1, ctx);
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else if (len2 == 1)
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_TEMPLATE(T, TEMPLATE(poly_evaluate, T)) (rop, op1, len1, op2,
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ctx);
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else /* len1 == 2 */
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_TEMPLATE(T, poly_compose_horner) (rop, op1, len1, op2, len2, ctx);
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return;
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}
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/* Initialisation */
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hlen = (slong *) flint_malloc(((len1 + 1) / 2) * sizeof(slong));
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k = FLINT_CLOG2(len1) - 1;
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hlen[0] = hlen[1] = ((1 << k) - 1) * (len2 - 1) + 1;
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for (i = k - 1; i > 0; i--)
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{
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slong hi = (len1 + (1 << i) - 1) / (1 << i);
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for (n = (hi + 1) / 2; n < hi; n++)
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hlen[n] = ((1 << i) - 1) * (len2 - 1) + 1;
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}
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powlen = (1 << k) * (len2 - 1) + 1;
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alloc = 0;
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for (i = 0; i < (len1 + 1) / 2; i++)
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alloc += hlen[i];
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v = _TEMPLATE(T, vec_init) (alloc + 2 * powlen, ctx);
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h = (TEMPLATE(T, struct) **) flint_malloc(((len1 + 1) / 2) *
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sizeof(TEMPLATE(T, struct) *));
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h[0] = v;
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for (i = 0; i < (len1 - 1) / 2; i++)
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{
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h[i + 1] = h[i] + hlen[i];
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hlen[i] = 0;
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}
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hlen[(len1 - 1) / 2] = 0;
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pow = v + alloc;
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temp = pow + powlen;
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/* Let's start the actual work */
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for (i = 0, j = 0; i < len1 / 2; i++, j += 2)
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{
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if (!TEMPLATE(T, is_zero) (op1 + (j + 1), ctx))
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{
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_TEMPLATE(T, TEMPLATE(poly_scalar_mul, T)) (h[i], op2, len2,
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op1 + j + 1, ctx);
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TEMPLATE(T, add) (h[i], h[i], op1 + j, ctx);
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hlen[i] = len2;
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}
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else if (!TEMPLATE(T, is_zero) (op1 + j, ctx))
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{
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TEMPLATE(T, set) (h[i], op1 + j, ctx);
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hlen[i] = 1;
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}
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}
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if ((len1 & WORD(1)))
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{
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if (!TEMPLATE(T, is_zero) (op1 + j, ctx))
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{
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TEMPLATE(T, set) (h[i], op1 + j, ctx);
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hlen[i] = 1;
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}
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}
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_TEMPLATE(T, poly_sqr) (pow, op2, len2, ctx);
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powlen = 2 * len2 - 1;
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for (n = (len1 + 1) / 2; n > 2; n = (n + 1) / 2)
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{
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if (hlen[1] > 0)
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{
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slong templen = powlen + hlen[1] - 1;
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_TEMPLATE(T, poly_mul) (temp, pow, powlen, h[1], hlen[1], ctx);
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_TEMPLATE(T, poly_add) (h[0], temp, templen, h[0], hlen[0], ctx);
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hlen[0] = FLINT_MAX(hlen[0], templen);
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}
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for (i = 1; i < n / 2; i++)
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{
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if (hlen[2 * i + 1] > 0)
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{
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_TEMPLATE(T, poly_mul) (h[i], pow, powlen, h[2 * i + 1],
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hlen[2 * i + 1], ctx);
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hlen[i] = hlen[2 * i + 1] + powlen - 1;
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}
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else
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hlen[i] = 0;
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_TEMPLATE(T, poly_add) (h[i], h[i], hlen[i], h[2 * i], hlen[2 * i],
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ctx);
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hlen[i] = FLINT_MAX(hlen[i], hlen[2 * i]);
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}
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if ((n & WORD(1)))
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{
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_TEMPLATE(T, poly_set) (h[i], h[2 * i], hlen[2 * i], ctx);
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hlen[i] = hlen[2 * i];
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}
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_TEMPLATE(T, poly_sqr) (temp, pow, powlen, ctx);
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powlen += powlen - 1;
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{
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TEMPLATE(T, struct) * t = pow;
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pow = temp;
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temp = t;
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}
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}
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_TEMPLATE(T, poly_mul) (rop, pow, powlen, h[1], hlen[1], ctx);
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_TEMPLATE(T, poly_add) (rop, rop, hlen[0], h[0], hlen[0], ctx);
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_TEMPLATE(T, vec_clear) (v, alloc + 2 * powlen, ctx);
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flint_free(h);
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flint_free(hlen);
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}
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void
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TEMPLATE(T, poly_compose_divconquer) (TEMPLATE(T, poly_t) rop,
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const TEMPLATE(T, poly_t) op1,
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const TEMPLATE(T, poly_t) op2,
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const TEMPLATE(T, ctx_t) ctx)
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{
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const slong len1 = op1->length;
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const slong len2 = op2->length;
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const slong lenr = (len1 - 1) * (len2 - 1) + 1;
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if (len1 == 0)
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{
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TEMPLATE(T, poly_zero) (rop, ctx);
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}
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else if (len1 == 1 || len2 == 0)
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{
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TEMPLATE(T, TEMPLATE(poly_set, T)) (rop, op1->coeffs + 0, ctx);
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}
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else if (rop != op1 && rop != op2)
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{
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TEMPLATE(T, poly_fit_length) (rop, lenr, ctx);
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_TEMPLATE(T, poly_compose_divconquer) (rop->coeffs, op1->coeffs, len1,
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op2->coeffs, len2, ctx);
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_TEMPLATE(T, poly_set_length) (rop, lenr, ctx);
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_TEMPLATE(T, poly_normalise) (rop, ctx);
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}
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else
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{
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TEMPLATE(T, poly_t) t;
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TEMPLATE(T, poly_init2) (t, lenr, ctx);
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_TEMPLATE(T, poly_compose_divconquer) (t->coeffs, op1->coeffs, len1,
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op2->coeffs, len2, ctx);
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_TEMPLATE(T, poly_set_length) (t, lenr, ctx);
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_TEMPLATE(T, poly_normalise) (t, ctx);
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TEMPLATE(T, poly_swap) (rop, t, ctx);
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TEMPLATE(T, poly_clear) (t, ctx);
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}
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}
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#endif
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