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/*
Copyright (C) 2016 Vincent Delecroix
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "fmpz.h"
#include "fmpz_poly.h"
void
fmpz_poly_power_sums(fmpz_poly_t res, const fmpz_poly_t poly, slong n)
{
slong len = poly->length;
if (len == 0)
{
flint_throw(FLINT_ERROR, "(fmpz_poly_power_sums): Zero polynomial.\n");
}
else if (n <= 0 || len == 1)
{
fmpz_poly_zero(res);
}
else
{
size_t i = 0;
while (fmpz_is_zero(poly->coeffs + i))
i++;
if (poly == res)
{
fmpz_poly_t t;
fmpz_poly_init2(t, n);
_fmpz_poly_power_sums_naive(t->coeffs, poly->coeffs + i,
len - i, n);
fmpz_poly_swap(res, t);
fmpz_poly_clear(t);
}
else
{
fmpz_poly_fit_length(res, n);
_fmpz_poly_power_sums_naive(res->coeffs, poly->coeffs + i,
len - i, n);
}
_fmpz_poly_set_length(res, n);
if (i)
fmpz_set_si(res->coeffs, len - 1);
_fmpz_poly_normalise(res);
}
}