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add support for non-unit coefficients

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2021-11-30 09:53:09 -08:00
parent 90bd5f186b
commit a81a00a93c
4 changed files with 210 additions and 90 deletions
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67
src/math/polysat/forbidden_intervals.cpp
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@ -29,9 +29,11 @@ namespace polysat {
* \returns True iff a forbidden interval exists and the output parameters were set.
*/
bool forbidden_intervals::get_interval(signed_constraint const& c, pvar v, eval_interval& out_interval, vector<signed_constraint>& out_side_cond) {
bool forbidden_intervals::get_interval(signed_constraint const& c, pvar v, rational & coeff, eval_interval& out_interval, vector<signed_constraint>& out_side_cond) {
if (!c->is_ule())
return false;
coeff = 1;
struct backtrack {
bool released = false;
@ -61,21 +63,26 @@ namespace polysat {
SASSERT(b1.is_val());
SASSERT(b2.is_val());
coeff = a1;
_backtrack.released = true;
// LOG("add " << c << " " << a1 << " " << b1 << " " << a2 << " " << b2);
if (match_linear1(c, a1, b1, e1, a2, b2, e2, out_interval, out_side_cond))
if (match_linear1(c, coeff, b1, e1, a2, b2, e2, out_interval, out_side_cond))
return true;
if (match_linear2(c, a1, b1, e1, a2, b2, e2, out_interval, out_side_cond))
if (match_linear2(c, coeff, b1, e1, a2, b2, e2, out_interval, out_side_cond))
return true;
if (match_linear3(c, a1, b1, e1, a2, b2, e2, out_interval, out_side_cond))
if (match_linear3(c, coeff, b1, e1, a2, b2, e2, out_interval, out_side_cond))
return true;
#if 0
if (match_linear4(c, a1, b1, e1, a2, b2, e2, out_interval, out_side_cond))
return true;
if (match_linear5(c, a1, b1, e1, a2, b2, e2, out_interval, out_side_cond))
return true;
#endif
_backtrack.released = false;
return false;
}
@ -114,7 +121,7 @@ namespace polysat {
};
eval_interval forbidden_intervals::to_interval(
signed_constraint const& c, bool is_trivial, rational const& coeff,
signed_constraint const& c, bool is_trivial, rational & coeff,
rational & lo_val, pdd & lo,
rational & hi_val, pdd & hi) {
@ -131,9 +138,12 @@ namespace polysat {
return eval_interval::full();
}
if (!coeff.is_one()) {
rational pow2 = m.max_value() + 1;
SASSERT(coeff == m.max_value());
rational pow2 = m.max_value() + 1;
if (coeff > pow2/2) {
coeff = pow2 - coeff;
SASSERT(coeff > 0);
// Transform according to: y \in [l;u[ <=> -y \in [1-u;1-l[
// -y \in [1-u;1-l[
// <=> -y - (1 - u) < (1 - l) - (1 - u) { by: y \in [l;u[ <=> y - l < u - l }
@ -156,14 +166,14 @@ namespace polysat {
}
/**
* Match e1 + t <= e2, with t = 2^j1*y
* Match e1 + t <= e2, with t = a1*y
* condition for empty/full: e2 == -1
*/
bool forbidden_intervals::match_linear1(signed_constraint const& c,
rational const& a1, pdd const& b1, pdd const& e1,
rational const& a2, pdd const& b2, pdd const& e2,
rational & a1, pdd const& b1, pdd const& e1,
rational const & a2, pdd const& b2, pdd const& e2,
eval_interval& interval, vector<signed_constraint>& side_cond) {
if (a2.is_zero() && coefficient_is_01(e1.manager(), a1)) {
if (a2.is_zero() && !a1.is_zero()) {
SASSERT(!a1.is_zero());
bool is_trivial = (b2 + 1).is_zero();
push_eq(is_trivial, e2 + 1, side_cond);
@ -178,36 +188,37 @@ namespace polysat {
}
/**
* e1 <= e2 + t, with t = 2^j2*y
* e1 <= e2 + t, with t = a2*y
* condition for empty/full: e1 == 0
*/
bool forbidden_intervals::match_linear2(signed_constraint const& c,
rational const& a1, pdd const& b1, pdd const& e1,
rational const& a2, pdd const& b2, pdd const& e2,
rational & a1, pdd const& b1, pdd const& e1,
rational const & a2, pdd const& b2, pdd const& e2,
eval_interval& interval, vector<signed_constraint>& side_cond) {
if (a1.is_zero() && coefficient_is_01(e1.manager(), a2)) {
if (a1.is_zero() && !a2.is_zero()) {
SASSERT(!a2.is_zero());
a1 = a2;
bool is_trivial = b1.is_zero();
push_eq(is_trivial, e1, side_cond);
auto lo = -e2;
rational lo_val = (-b2).val();
auto hi = e1 - e2;
rational hi_val = (b1 - b2).val();
interval = to_interval(c, is_trivial, a2, lo_val, lo, hi_val, hi);
interval = to_interval(c, is_trivial, a1, lo_val, lo, hi_val, hi);
return true;
}
return false;
}
/**
* e1 + t <= e2 + t, with t = 2^j1*y = 2^j2*y
* condition for empty/full: e1 == e2/
* e1 + t <= e2 + t, with t = a1*y = a2*y
* condition for empty/full: e1 == e2
*/
bool forbidden_intervals::match_linear3(signed_constraint const& c,
rational const& a1, pdd const& b1, pdd const& e1,
rational const& a2, pdd const& b2, pdd const& e2,
rational & a1, pdd const& b1, pdd const& e1,
rational const & a2, pdd const& b2, pdd const& e2,
eval_interval& interval, vector<signed_constraint>& side_cond) {
if (coefficient_is_01(e1.manager(), a1) && coefficient_is_01(e1.manager(), a2) && a1 == a2 && !a1.is_zero()) {
if (a1 == a2 && !a1.is_zero()) {
bool is_trivial = b1.val() == b2.val();
push_eq(is_trivial, e1 - e2, side_cond);
auto lo = -e2;
@ -220,12 +231,13 @@ namespace polysat {
return false;
}
#if 0
/**
* a1*y + e1 = 0, with a1 odd
*/
bool forbidden_intervals::match_linear4(signed_constraint const& c,
rational const& a1, pdd const& b1, pdd const& e1,
rational const& a2, pdd const& b2, pdd const& e2,
rational & a1, pdd const& b1, pdd const& e1,
rational & a2, pdd const& b2, pdd const& e2,
eval_interval& interval, vector<signed_constraint>& side_cond) {
if (a1.is_odd() && a2.is_zero() && b2.val().is_zero()) {
push_eq(true, e2, side_cond);
@ -257,8 +269,8 @@ namespace polysat {
* - c < ax + b
*/
bool forbidden_intervals::match_linear5(signed_constraint const& c,
rational const& a1, pdd const& b1, pdd const& e1,
rational const& a2, pdd const& b2, pdd const& e2,
rational & a1, pdd const& b1, pdd const& e1,
rational & a2, pdd const& b2, pdd const& e2,
eval_interval& interval, vector<signed_constraint>& side_cond) {
auto& m = e1.manager();
@ -323,4 +335,5 @@ namespace polysat {
}
return false;
}
#endif
}