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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 "qqbar.h"
int
qqbar_cmpabs(const qqbar_t x, const qqbar_t y)
{
slong prec;
acb_t z1, z2;
arb_t z3, z4;
int res;
if (qqbar_sgn_im(x) == 0 && qqbar_sgn_im(y) == 0)
return qqbar_cmpabs_re(x, y);
if (qqbar_sgn_re(x) == 0 && qqbar_sgn_re(y) == 0)
return qqbar_cmpabs_im(x, y);
{
acb_init(z1);
acb_init(z2);
arb_init(z3);
arb_init(z4);
acb_set(z1, QQBAR_ENCLOSURE(x));
acb_set(z2, QQBAR_ENCLOSURE(y));
res = 0;
for (prec = QQBAR_DEFAULT_PREC / 2; ; prec *= 2)
{
_qqbar_enclosure_raw(z1, QQBAR_POLY(x), z1, prec);
_qqbar_enclosure_raw(z2, QQBAR_POLY(y), z2, prec);
acb_abs(z3, z1, prec);
acb_abs(z4, z2, prec);
if (!arb_overlaps(z3, z4))
{
res = arf_cmpabs(arb_midref(z3), arb_midref(z4));
break;
}
/* Force an exact computation (may be slow) */
if (prec >= 4 * QQBAR_DEFAULT_PREC)
{
qqbar_t t, u;
qqbar_init(t);
qqbar_init(u);
qqbar_abs2(t, x);
qqbar_abs2(u, y);
res = qqbar_cmp_re(t, u);
qqbar_clear(t);
qqbar_clear(u);
break;
}
}
acb_clear(z1);
acb_clear(z2);
arb_clear(z3);
arb_clear(z4);
}
return res;
}