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/*
Copyright (C) 2020 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 "ca.h"
truth_t
ca_check_is_neg_one(const ca_t x, ca_ctx_t ctx)
{
if (CA_IS_SPECIAL(x))
{
if (ca_is_unknown(x, ctx))
return T_UNKNOWN;
return T_FALSE;
}
else if (CA_IS_QQ(x, ctx))
{
if (fmpz_is_one(fmpq_denref(CA_FMPQ(x))) && fmpz_equal_si(fmpq_numref(CA_FMPQ(x)), -1))
return T_TRUE;
else
return T_FALSE;
}
else if (CA_IS_QQ_I(x, ctx))
{
const fmpz *n, *d;
n = QNF_ELEM_NUMREF(CA_NF_ELEM(x));
d = QNF_ELEM_NUMREF(CA_NF_ELEM(x));
if (fmpz_is_one(d) && fmpz_equal_si(n, -1) && fmpz_is_zero(n + 1))
return T_TRUE;
return T_FALSE;
}
else
{
truth_t res;
ca_t t;
ca_init(t, ctx);
ca_set_si(t, -1, ctx);
res = ca_check_equal(x, t, ctx);
ca_clear(t, ctx);
return res;
}
}