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/*
Copyright (C) 2014 Fredrik Johansson
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_vec.h"
#include "fmpq_poly.h"
void
fmpq_poly_set_trunc(fmpq_poly_t res, const fmpq_poly_t poly, slong n)
{
if (poly == res)
{
fmpq_poly_truncate(res, n);
}
else
{
slong rlen;
rlen = FLINT_MIN(n, poly->length);
while (rlen > 0 && fmpz_is_zero(poly->coeffs + rlen - 1))
rlen--;
fmpq_poly_fit_length(res, rlen);
_fmpz_vec_set(res->coeffs, poly->coeffs, rlen);
fmpz_set(res->den, poly->den);
_fmpq_poly_set_length(res, rlen);
fmpq_poly_canonicalise(res);
}
}