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/********************* */
/*! \file intersection.cpp
** \verbatim
** Top contributors (to current version):
** Gereon Kremer
** This file is part of the CVC4 project.
** Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
** in the top-level source directory and their institutional affiliations.
** All rights reserved. See the file COPYING in the top-level source
** directory for licensing information.\endverbatim
**
** \brief
**/
#include "theory/arith/nl/icp/intersection.h"
#ifdef CVC4_POLY_IMP
#include <iostream>
#include <poly/polyxx.h>
#include "base/check.h"
#include "base/output.h"
#include "theory/arith/nl/poly_conversion.h"
namespace CVC4 {
namespace theory {
namespace arith {
namespace nl {
namespace icp {
PropagationResult intersect_interval_with(poly::Interval& cur,
const poly::Interval& res,
std::size_t size_threshold)
{
Trace("nl-icp") << cur << " := " << cur << " intersected with " << res
<< std::endl;
if (bitsize(get_lower(res)) > size_threshold
|| bitsize(get_upper(res)) > size_threshold)
{
Trace("nl-icp") << "Reached bitsize threshold" << std::endl;
return PropagationResult::NOT_CHANGED;
}
// Basic idea to organize this function:
// The bounds for res have 5 positions:
// 1 < 2 (lower(cur)) < 3 < 4 (upper(cur)) < 5
if (get_upper(res) < get_lower(cur))
{
// upper(res) at 1
Trace("nl-icp") << "res < cur -> conflict" << std::endl;
return PropagationResult::CONFLICT;
}
if (get_upper(res) == get_lower(cur))
{
// upper(res) at 2
if (get_upper_open(res) || get_lower_open(cur))
{
Trace("nl-icp") << "meet at lower, but one is open -> conflict"
<< std::endl;
return PropagationResult::CONFLICT;
}
if (!is_point(cur))
{
Trace("nl-icp") << "contracts to point interval at lower" << std::endl;
cur = poly::Interval(get_upper(res));
return PropagationResult::CONTRACTED;
}
return PropagationResult::NOT_CHANGED;
}
Assert(get_upper(res) > get_lower(cur))
<< "Comparison operator does weird stuff.";
if (get_upper(res) < get_upper(cur))
{
// upper(res) at 3
if (get_lower(res) < get_lower(cur))
{
// lower(res) at 1
Trace("nl-icp") << "lower(cur) .. upper(res)" << std::endl;
cur.set_upper(get_upper(res), get_upper_open(res));
return PropagationResult::CONTRACTED;
}
if (get_lower(res) == get_lower(cur))
{
// lower(res) at 2
Trace("nl-icp") << "meet at lower, lower(cur) .. upper(res)" << std::endl;
cur = poly::Interval(get_lower(cur),
get_lower_open(cur) || get_lower_open(res),
get_upper(res),
get_upper_open(res));
if (get_lower_open(cur) && !get_lower_open(res))
{
return PropagationResult::CONTRACTED;
}
return PropagationResult::CONTRACTED_WITHOUT_CURRENT;
}
Assert(get_lower(res) > get_lower(cur))
<< "Comparison operator does weird stuff.";
// lower(res) at 3
Trace("nl-icp") << "cur covers res" << std::endl;
cur = res;
return PropagationResult::CONTRACTED_WITHOUT_CURRENT;
}
if (get_upper(res) == get_upper(cur))
{
// upper(res) at 4
if (get_lower(res) < get_lower(cur))
{
// lower(res) at 1
Trace("nl-icp") << "res covers cur but meet at upper" << std::endl;
if (get_upper_open(res) && !get_upper_open(cur))
{
cur.set_upper(get_upper(cur), true);
return PropagationResult::CONTRACTED;
}
return PropagationResult::NOT_CHANGED;
}
if (get_lower(res) == get_lower(cur))
{
// lower(res) at 2
Trace("nl-icp") << "same bounds but check openness" << std::endl;
bool changed = false;
if (get_lower_open(res) && !get_lower_open(cur))
{
changed = true;
cur.set_lower(get_lower(cur), true);
}
if (get_upper_open(res) && !get_upper_open(cur))
{
changed = true;
cur.set_upper(get_upper(cur), true);
}
if (changed)
{
if ((get_lower_open(res) || !get_upper_open(cur))
&& (get_upper_open(res) || !get_upper_open(cur)))
{
return PropagationResult::CONTRACTED_WITHOUT_CURRENT;
}
return PropagationResult::CONTRACTED;
}
return PropagationResult::NOT_CHANGED;
}
Assert(get_lower(res) > get_lower(cur))
<< "Comparison operator does weird stuff.";
// lower(res) at 3
Trace("nl-icp") << "cur covers res but meet at upper" << std::endl;
cur = poly::Interval(get_lower(res),
get_lower_open(res),
get_upper(res),
get_upper_open(cur) || get_upper_open(res));
if (get_upper_open(cur) && !get_upper_open(res))
{
return PropagationResult::CONTRACTED;
}
return PropagationResult::CONTRACTED_WITHOUT_CURRENT;
}
Assert(get_upper(res) > get_upper(cur))
<< "Comparison operator does weird stuff.";
// upper(res) at 5
if (get_lower(res) < get_lower(cur))
{
// lower(res) at 1
Trace("nl-icp") << "res covers cur" << std::endl;
return PropagationResult::NOT_CHANGED;
}
if (get_lower(res) == get_lower(cur))
{
// lower(res) at 2
Trace("nl-icp") << "res covers cur but meet at lower" << std::endl;
if (get_lower_open(res) && is_point(cur))
{
return PropagationResult::CONFLICT;
}
else if (get_lower_open(res) && !get_lower_open(cur))
{
cur.set_lower(get_lower(cur), true);
return PropagationResult::CONTRACTED;
}
return PropagationResult::NOT_CHANGED;
}
Assert(get_lower(res) > get_lower(cur))
<< "Comparison operator does weird stuff.";
if (get_lower(res) < get_upper(cur))
{
// lower(res) at 3
Trace("nl-icp") << "lower(res) .. upper(cur)" << std::endl;
cur.set_lower(get_lower(res), get_lower_open(res));
return PropagationResult::CONTRACTED;
}
if (get_lower(res) == get_upper(cur))
{
// lower(res) at 4
if (get_lower_open(res) || get_upper_open(cur))
{
Trace("nl-icp") << "meet at upper, but one is open -> conflict"
<< std::endl;
return PropagationResult::CONFLICT;
}
if (!is_point(cur))
{
Trace("nl-icp") << "contracts to point interval at upper" << std::endl;
cur = poly::Interval(get_lower(res));
return PropagationResult::CONTRACTED;
}
return PropagationResult::NOT_CHANGED;
}
Assert(get_lower(res) > get_upper(cur));
// lower(res) at 5
Trace("nl-icp") << "res > cur -> conflict" << std::endl;
return PropagationResult::CONFLICT;
}
} // namespace icp
} // namespace nl
} // namespace arith
} // namespace theory
} // namespace CVC4
#endif
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