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Use M for 2^N

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This commit is contained in:
Jakob Rath 2023-01-10 14:50:11 +01:00
parent 913aa9f43e
commit abbe139abb
2 changed files with 25 additions and 20 deletions
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41
src/math/polysat/saturation.cpp
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@ -1503,21 +1503,24 @@ namespace polysat {
}
rational saturation::round(rational const& N, rational const& x) {
SASSERT(0 <= x && x < N);
if (x + N/2 > N)
return x - N;
rational saturation::round(rational const& M, rational const& x) {
SASSERT(0 <= x && x < M);
if (x + M/2 > M)
return x - M;
else
return x;
}
/**
* write as q := a*y + b
*/
bool saturation::extract_linear_form(pdd const& q, pvar& y, rational& a, rational& b) {
auto & m = q.manager();
auto N = m.two_to_N();
auto M = m.two_to_N();
if (q.is_val()) {
a = 0;
b = round(N, q.val());
b = round(M, q.val());
return true;
}
y = q.var();
@ -1525,8 +1528,8 @@ namespace polysat {
return false;
if (!q.hi().is_val())
return false;
a = round(N, q.hi().val());
b = round(N, q.lo().val());
a = round(M, q.hi().val());
b = round(M, q.lo().val());
return true;
}
@ -1535,11 +1538,11 @@ namespace polysat {
*/
bool saturation::extract_bilinear_form(pvar x, pdd const& p, pvar& y, rational& a, rational& b, rational& c, rational& d) {
auto & m = s.var2pdd(x);
auto N = m.two_to_N();
auto M = m.two_to_N();
auto eval_round = [&](pdd const& p, rational& r) {
if (!s.try_eval(p, r))
return false;
r = round(N, r);
r = round(M, r);
return true;
};
switch (p.degree(x)) {
@ -1582,27 +1585,29 @@ namespace polysat {
}
/**
* update d such that for every value x_min <= x <= x_max 0 <= a*x*y0 + b*x + c*y0 + d < N
* update d such that 0 <= a*x*y0 + b*x + c*y0 + d < M for every value x_min <= x <= x_max
* return false if there is no such d.
*/
bool saturation::adjust_bound(rational const& x_min, rational const& x_max, rational const& y0, rational const& N, rational const& a, rational const& b, rational const& c, rational& d) {
bool saturation::adjust_bound(rational const& x_min, rational const& x_max, rational const& y0, rational const& M, rational const& a, rational const& b, rational const& c, rational& d) {
SASSERT(x_min <= x_max);
rational A = a*y0 + b;
rational B = c*y0 + d;
rational max = A >= 0 ? x_max * A + B : x_min * A + B;
rational min = A >= 0 ? x_min * A + B : x_max * A + B;
if (max - min >= N)
VERIFY(min <= max);
if (max - min >= M)
return false;
rational offset = rational::zero();
if (max > N) // TODO: what if max == N?
offset = -N * floor(max / N);
if (max > M) // TODO: what if max == M?
offset = -M * floor(max / M);
else if (max < 0)
offset = N * floor((-max + N - 1) / N);
offset = M * floor((-max + M - 1) / M);
d += offset;
if (min + offset < 0) // [min,max] contains a multiple of N ... we could try splitting the x-interval into two intervals
if (min + offset < 0) // [min,max] contains a multiple of M ... we could try splitting the x-interval into two intervals
return false;
VERIFY(min + offset < N);
VERIFY(min + offset < M);
return true;
}

4
src/math/polysat/saturation.h
View file

@ -71,10 +71,10 @@ namespace polysat {
bool try_add_mul_bound2(pvar x, conflict& core, inequality const& axb_l_y);
bool try_infer_parity_equality(pvar x, conflict& core, inequality const& a_l_b);
rational round(rational const& N, rational const& x);
rational round(rational const& M, rational const& x);
bool extract_linear_form(pdd const& q, pvar& y, rational& a, rational& b);
bool extract_bilinear_form(pvar x, pdd const& p, pvar& y, rational& a, rational& b, rational& c, rational& d);
bool adjust_bound(rational const& x_min, rational const& x_max, rational const& y0, rational const& N, rational const& a, rational const& b, rational const& c, rational& d);
bool adjust_bound(rational const& x_min, rational const& x_max, rational const& y0, rational const& M, rational const& a, rational const& b, rational const& c, rational& d);
bool update_min(rational& y_min, rational const& x_min, rational const& x_max, rational const& a, rational const& b, rational const& c, rational const& d);
bool update_max(rational& y_max, rational const& x_min, rational const& x_max, rational const& a, rational const& b, rational const& c, rational const& d);
void fix_values(pvar x, pvar y, pdd const& p);