pqc/external/flint-2.4.3/fq_poly_templates/compose_horner.c

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2014-05-18 22:03:37 +00:00
/*=============================================================================
This file is part of FLINT.
FLINT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FLINT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2012 Sebastian Pancratz
Copyright (C) 2013 Mike Hansen
******************************************************************************/
#ifdef T
#include "templates.h"
void
_TEMPLATE(T, poly_compose_horner) (TEMPLATE(T, struct) * rop,
const TEMPLATE(T, struct) * op1, slong len1,
const TEMPLATE(T, struct) * op2, slong len2,
const TEMPLATE(T, ctx_t) ctx)
{
if (len1 == 1)
{
TEMPLATE(T, set) (rop, op1 + 0, ctx);
}
else
{
const slong alloc = (len1 - 1) * (len2 - 1) + 1;
slong i = len1 - 1, lenr;
TEMPLATE(T, struct) * t = _TEMPLATE(T, vec_init) (alloc, ctx);
/*
Perform the first two steps as one,
"res = a(m) * poly2 + a(m-1)".
*/
{
lenr = len2;
_TEMPLATE(T, TEMPLATE(poly_scalar_mul, T)) (rop, op2, len2,
op1 + i, ctx);
i--;
TEMPLATE(T, add) (rop + 0, rop + 0, op1 + i, ctx);
}
while (i--)
{
_TEMPLATE(T, poly_mul) (t, rop, lenr, op2, len2, ctx);
lenr += len2 - 1;
_TEMPLATE(T, poly_add) (rop, t, lenr, op1 + i, 1, ctx);
}
_TEMPLATE(T, vec_clear) (t, alloc, ctx);
}
}
void
TEMPLATE(T, poly_compose_horner) (TEMPLATE(T, poly_t) rop,
const TEMPLATE(T, poly_t) op1,
const TEMPLATE(T, poly_t) op2,
const TEMPLATE(T, ctx_t) ctx)
{
const slong len1 = op1->length;
const slong len2 = op2->length;
const slong lenr = (len1 - 1) * (len2 - 1) + 1;
if (len1 == 0)
{
TEMPLATE(T, poly_zero) (rop, ctx);
}
else if (len1 == 1 || len2 == 0)
{
TEMPLATE(T, TEMPLATE(poly_set, T)) (rop, op1->coeffs + 0, ctx);
}
else if (rop != op1 && rop != op2)
{
TEMPLATE(T, poly_fit_length) (rop, lenr, ctx);
_TEMPLATE(T, poly_compose_horner) (rop->coeffs, op1->coeffs, len1,
op2->coeffs, len2, ctx);
_TEMPLATE(T, poly_set_length) (rop, lenr, ctx);
_TEMPLATE(T, poly_normalise) (rop, ctx);
}
else
{
TEMPLATE(T, poly_t) t;
TEMPLATE(T, poly_init2) (t, lenr, ctx);
_TEMPLATE(T, poly_compose_horner) (t->coeffs, op1->coeffs, len1,
op2->coeffs, len2, ctx);
_TEMPLATE(T, poly_set_length) (t, lenr, ctx);
_TEMPLATE(T, poly_normalise) (t, ctx);
TEMPLATE(T, poly_swap) (rop, t, ctx);
TEMPLATE(T, poly_clear) (t, ctx);
}
}
#endif