167 lines
4.5 KiB
C
167 lines
4.5 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) 2010, 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_pow) (TEMPLATE(T, struct) * rop,
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const TEMPLATE(T, struct) * op, slong len, ulong e,
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const TEMPLATE(T, ctx_t) ctx)
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{
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ulong bit = ~((~UWORD(0)) >> 1);
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slong rlen;
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slong alloc = (slong) e * (len - 1) + 1;
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TEMPLATE(T, struct) * v = _TEMPLATE(T, vec_init) (alloc, ctx);
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TEMPLATE(T, struct) * R, *S, *T;
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/*
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Set bits to the bitmask with a 1 one place lower than the msb of e
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*/
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while ((bit & e) == UWORD(0))
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bit >>= 1;
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bit >>= 1;
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/*
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Trial run without any polynomial arithmetic to determine the parity
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of the number of swaps; then set R and S accordingly
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*/
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{
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unsigned int swaps = 0U;
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ulong bit2 = bit;
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if ((bit2 & e))
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swaps = ~swaps;
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while (bit2 >>= 1)
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if ((bit2 & e) == UWORD(0))
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swaps = ~swaps;
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if (swaps == 0U)
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{
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R = rop;
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S = v;
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}
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else
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{
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R = v;
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S = rop;
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}
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}
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/*
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We unroll the first step of the loop, referring to {poly, len}
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*/
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_TEMPLATE(T, poly_sqr) (R, op, len, ctx);
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rlen = 2 * len - 1;
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if ((bit & e))
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{
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_TEMPLATE(T, poly_mul) (S, R, rlen, op, len, ctx);
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rlen += len - 1;
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T = R;
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R = S;
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S = T;
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}
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while ((bit >>= 1))
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{
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if ((bit & e))
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{
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_TEMPLATE(T, poly_sqr) (S, R, rlen, ctx);
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rlen += rlen - 1;
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_TEMPLATE(T, poly_mul) (R, S, rlen, op, len, ctx);
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rlen += len - 1;
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}
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else
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{
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_TEMPLATE(T, poly_sqr) (S, R, rlen, ctx);
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rlen += rlen - 1;
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T = R;
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R = S;
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S = T;
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}
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}
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_TEMPLATE(T, vec_clear) (v, alloc, ctx);
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}
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void
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TEMPLATE(T, poly_pow) (TEMPLATE(T, poly_t) rop, const TEMPLATE(T, poly_t) op,
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ulong e, const TEMPLATE(T, ctx_t) ctx)
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{
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const slong len = op->length;
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if ((len < 2) | (e < UWORD(3)))
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{
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if (e == UWORD(0))
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TEMPLATE(T, poly_one) (rop, ctx);
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else if (len == 0)
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TEMPLATE(T, poly_zero) (rop, ctx);
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else if (len == 1)
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{
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fmpz_t f;
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fmpz_init_set_ui(f, e);
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TEMPLATE(T, poly_fit_length) (rop, 1, ctx);
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TEMPLATE(T, pow) (rop->coeffs + 0, op->coeffs + 0, f, ctx);
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_TEMPLATE(T, poly_set_length) (rop, 1, ctx);
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fmpz_clear(f);
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}
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else if (e == UWORD(1))
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TEMPLATE(T, poly_set) (rop, op, ctx);
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else /* e == UWORD(2) */
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TEMPLATE(T, poly_sqr) (rop, op, ctx);
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}
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else
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{
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const slong rlen = (slong) e * (len - 1) + 1;
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if (rop != op)
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{
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TEMPLATE(T, poly_fit_length) (rop, rlen, ctx);
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_TEMPLATE(T, poly_pow) (rop->coeffs, op->coeffs, len, e, ctx);
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_TEMPLATE(T, poly_set_length) (rop, rlen, 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, rlen, ctx);
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_TEMPLATE(T, poly_pow) (t->coeffs, op->coeffs, len, e, ctx);
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_TEMPLATE(T, poly_set_length) (t, rlen, 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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}
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#endif
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