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inverse approx

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2021-05-07 17:33:07 -07:00
parent e3e2860198
commit 654892fec1
2 changed files with 80 additions and 28 deletions
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21
src/math/polysat/fixplex.h
View file

@ -47,12 +47,17 @@ namespace polysat {
*/
template<typename Numeral>
struct interval {
bool emp { false };
Numeral lo { 0 };
Numeral hi { 0 };
interval() {}
interval(Numeral const& l, Numeral const& h): lo(l), hi(h) {}
static interval free() { return interval(0, 0); }
static interval empty() { interval i(0, 0); i.emp = true; return i; }
bool is_free() const { return lo == hi; }
bool is_empty() const { return emp; }
bool contains(Numeral const& n) const;
interval operator&(interval const& other) const;
interval operator+(interval const& other) const;
interval operator-(interval const& other) const;
interval operator-() const;
@ -60,7 +65,11 @@ namespace polysat {
interval operator+(Numeral const& n) const { return interval(lo + n, hi + n); }
interval operator-(Numeral const& n) const { return interval(lo - n, hi - n); }
interval& operator+=(interval const& other) { *this = *this + other; return *this; }
std::ostream& display(std::ostream& out) const { return out << "[" << pp(lo) << ", " << pp(hi) << "["; }
std::ostream& display(std::ostream& out) const {
if (is_empty()) return out << "empty";
if (is_free()) return out << "free";
return out << "[" << pp(lo) << ", " << pp(hi) << "[";
}
};
template<typename Numeral>
@ -109,6 +118,10 @@ namespace polysat {
m_base2row(0),
m_is_base(false)
{}
var_info& operator&=(interval<numeral> const& range) {
interval<numeral>::operator=(range);
return *this;
}
};
struct row_info {
@ -203,7 +216,7 @@ namespace polysat {
void fixed_var_eh(row const& r, var_t x);
void eq_eh(var_t x, var_t y, row const& r1, row const& r2);
void propagate_bounds(row const& r);
void new_bound(row const& r, var_t x, numeral const& l, numeral const& h);
void new_bound(row const& r, var_t x, interval<numeral> const& range);
void pivot(var_t x_i, var_t x_j, numeral const& b, numeral const& value);
numeral value2delta(var_t v, numeral const& new_value) const;
void update_value(var_t v, numeral const& delta);
@ -211,8 +224,8 @@ namespace polysat {
bool has_minimal_trailing_zeros(var_t y, numeral const& b);
var_t select_pivot_core(var_t x, numeral const& new_value, numeral& out_b);
bool in_bounds(var_t v) const { return in_bounds(v, value(v)); }
bool in_bounds(var_t v, numeral const& b) const { return in_bounds(b, lo(v), hi(v)); }
bool in_bounds(numeral const& val, numeral const& lo, numeral const& hi) const;
bool in_bounds(var_t v, numeral const& b) const { return in_bounds(b, m_vars[v]); }
bool in_bounds(numeral const& val, interval<numeral> const& range) const { return range.contains(val); }
bool is_free(var_t v) const { return lo(v) == hi(v); }
bool is_non_free(var_t v) const { return !is_free(v); }
bool is_fixed(var_t v) const { return lo(v) + 1 == hi(v); }

87
src/math/polysat/fixplex_def.h
View file

@ -23,8 +23,24 @@ Author:
namespace polysat {
template<typename Numeral>
bool interval<Numeral>::contains(Numeral const& n) const {
if (is_empty())
return false;
if (is_free())
return true;
if (lo < hi)
return lo <= n && n < hi;
else
return lo <= n || n < hi;
}
template<typename Numeral>
interval<Numeral> interval<Numeral>::operator+(interval<Numeral> const& other) const {
if (is_empty())
return *this;
if (other.is_empty())
return other;
if (is_free())
return *this;
if (other.is_free())
@ -42,6 +58,8 @@ namespace polysat {
template<typename Numeral>
interval<Numeral> interval<Numeral>::operator-() const {
if (is_empty())
return *this;
if (is_free())
return *this;
return interval(1 - hi, 1 - lo);
@ -49,6 +67,8 @@ namespace polysat {
template<typename Numeral>
interval<Numeral> interval<Numeral>::operator*(Numeral const& n) const {
if (is_empty())
return *this;
if (n == 0)
return interval(0, 1);
if (n == 1)
@ -71,6 +91,26 @@ namespace polysat {
}
}
template<typename Numeral>
interval<Numeral> interval<Numeral>::operator&(interval const& other) const {
Numeral l, h;
if (is_free() || other.is_empty())
return other;
if (other.is_free() || is_empty())
return *this;
if (contains(other.lo))
l = other.lo;
else if (other.contains(lo))
l = lo;
else interval::empty();
if (contains(other.hi - 1))
h = other.hi;
else if (other.contains(hi - 1))
h = hi;
return interval(l, h);
}
template<typename Ext>
fixplex<Ext>::~fixplex() {
reset();
@ -228,14 +268,6 @@ namespace polysat {
}
template<typename Ext>
bool fixplex<Ext>::in_bounds(numeral const& val, numeral const& lo, numeral const& hi) const {
if (lo == hi)
return true;
if (lo < hi)
return lo <= val && val < hi;
return val < hi || lo <= val;
}
/**
* Attempt to improve assigment to make x feasible.
@ -267,6 +299,8 @@ namespace polysat {
pivot(x, y, b, new_value);
std::cout << "pivot v" << y << " := " << new_value << "\n";
// get_offset_eqs(row(base2row(y)));
return l_true;
@ -304,7 +338,7 @@ namespace polysat {
if (!has_minimal_trailing_zeros(y, b))
continue;
numeral new_y_value = (row_value - b*value(y) - a*new_value)/b;
bool _in_bounds = in_bounds(new_y_value, lo(y), hi(y));
bool _in_bounds = in_bounds(y, new_y_value);
if (!_in_bounds) {
if (lo(y) - new_y_value < new_y_value - hi(y))
delta_y = new_y_value - lo(y);
@ -520,6 +554,7 @@ namespace polysat {
numeral old_value_y = yI.m_value;
row_x.m_base = y;
row_x.m_value = row_x.m_value - b*old_value_y + a*new_value;
std::cout << "row value " << row_x.m_value << "\n";
row_x.m_base_coeff = b;
yI.m_base2row = rx;
yI.m_is_base = true;
@ -663,7 +698,15 @@ namespace polysat {
void fixplex<Ext>::set_base_value(var_t x) {
SASSERT(is_base(x));
row r(base2row(x));
m_vars[x].m_value = 0 - (row2value(r) / row2base_coeff(r));
auto c = row2base_coeff(r);
if (c == 1)
m_vars[x].m_value = 0 - row2value(r);
else if (c + 1 == 0)
m_vars[x].m_value = row2value(r);
else {
// TBD: compute "inverse" of c?
m_vars[x].m_value = 0 - row2value(r) / c;
}
bool was_integral = row2integral(r);
m_rows[r.id()].m_integral = is_solved(r);
if (was_integral && !row2integral(r))
@ -808,29 +851,25 @@ namespace polysat {
if (free_v != null_var) {
range = (-range) * free_c;
if (range.is_free())
return;
new_bound(r, free_v, range.lo, range.hi);
new_bound(r, free_v, range);
SASSERT(in_bounds(free_v));
return;
}
for (auto const& e : M.row_entries(r)) {
var_t v = e.var();
SASSERT(!is_free(v));
numeral const& c = e.coeff();
auto range1 = range - m_vars[v] * c;
new_bound(r, v, range1.lo, range1.hi);
auto range1 = range - m_vars[v] * e.coeff();
new_bound(r, v, range1);
// SASSERT(in_bounds(v));
}
}
template<typename Ext>
void fixplex<Ext>::new_bound(row const& r, var_t x, numeral const& l, numeral const& h) {
// TBD:
std::cout << is_free(x) << " " << l << " " << lo(x) << " " << hi(x) << " " << h << "\n";
if (!is_free(x) && l <= lo(x) && hi(x) <= h)
return;
IF_VERBOSE(0, verbose_stream() << "new-bound v" << x << " [" << pp(l) << "," << pp(h) << "[\n");
void fixplex<Ext>::new_bound(row const& r, var_t x, interval<numeral> const& range) {
if (range.is_free())
return;
m_vars[x] &= range;
IF_VERBOSE(0, verbose_stream() << "new-bound v" << x << " " << m_vars[x] << "\n");
}
template<typename Ext>
@ -838,7 +877,7 @@ namespace polysat {
M.display(out);
for (unsigned i = 0; i < m_vars.size(); ++i) {
var_info const& vi = m_vars[i];
out << "v" << i << " " << pp(value(i)) << " [" << pp(lo(i)) << ", " << pp(hi(i)) << "[ ";
out << "v" << i << " " << pp(value(i)) << " " << vi << " ";
if (vi.m_is_base) out << "b:" << vi.m_base2row << " ";
out << "\n";
}
@ -853,7 +892,7 @@ namespace polysat {
out << pp(e.coeff()) << " * ";
out << "v" << v << " ";
if (values)
out << pp(value(v)) << " [" << pp(lo(v)) << ", " << pp(hi(v)) << "[ ";
out << pp(value(v)) << " " << m_vars[v];
}
return out << "\n";
}