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speed up freedom interval computation

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-01-28 15:21:39 -08:00
parent 75d1e8e929
commit ff5bdd6f1f
3 changed files with 86 additions and 30 deletions
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78
src/math/lp/int_solver.cpp
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@ -464,7 +464,7 @@ void int_solver::patch_nbasic_column(unsigned j, bool patch_only_int_vals) {
impq & val = lcs.m_r_x[j];
bool val_is_int = val.is_int();
if (patch_only_int_vals && !val_is_int)
return;
return;
bool inf_l, inf_u;
impq l, u;
@ -473,11 +473,13 @@ void int_solver::patch_nbasic_column(unsigned j, bool patch_only_int_vals) {
return;
}
bool m_is_one = m.is_one();
if (m.is_one() && val_is_int)
if (m.is_one() && val_is_int) {
return;
}
// check whether value of j is already a multiple of m.
if (val_is_int && (val.x / m).is_int())
if (val_is_int && (val.x / m).is_int()) {
return;
}
TRACE("patch_int",
tout << "TARGET j" << j << " -> [";
if (inf_l) tout << "-oo"; else tout << l;
@ -488,25 +490,21 @@ void int_solver::patch_nbasic_column(unsigned j, bool patch_only_int_vals) {
if (!inf_l) {
l = impq(m_is_one ? ceil(l) : m * ceil(l / m));
if (inf_u || l <= u) {
TRACE("patch_int",
tout << "patching with l: " << l << '\n';);
TRACE("patch_int", tout << "patching with l: " << l << '\n';);
m_lar_solver->set_value_for_nbasic_column(j, l);
}
else {
TRACE("patch_int",
tout << "not patching " << l << "\n";);
TRACE("patch_int", tout << "not patching " << l << "\n";);
}
}
else if (!inf_u) {
u = impq(m_is_one ? floor(u) : m * floor(u / m));
m_lar_solver->set_value_for_nbasic_column(j, u);
TRACE("patch_int",
tout << "patching with u: " << u << '\n';);
TRACE("patch_int", tout << "patching with u: " << u << '\n';);
}
else {
m_lar_solver->set_value_for_nbasic_column(j, impq(0));
TRACE("patch_int",
tout << "patching with 0\n";);
TRACE("patch_int", tout << "patching with 0\n";);
}
}
@ -758,39 +756,69 @@ bool int_solver::get_freedom_interval_for_column(unsigned j, bool & inf_l, impq
m = mpq(1);
if (has_low(j)) {
set_lower(l, inf_l, lower_bound(j));
set_lower(l, inf_l, lower_bound(j) - xj);
}
if (has_upper(j)) {
set_upper(u, inf_u, upper_bound(j));
set_upper(u, inf_u, upper_bound(j) - xj);
}
mpq a; // the coefficient in the column
unsigned row_index;
lp_assert(settings().use_tableau());
const auto & A = m_lar_solver->A_r();
unsigned rounds = 0;
for (const auto &c : A.column(j)) {
row_index = c.var();
const mpq & a = c.coeff();
const mpq & a = c.coeff();
unsigned i = lcs.m_r_basis[row_index];
impq const & xi = get_value(i);
if (column_is_int(i) && column_is_int(j) && !a.is_int())
m = lcm(m, denominator(a));
}
if (column_is_int(j) && m.is_one())
return false;
for (const auto &c : A.column(j)) {
if (!inf_l && !inf_u && l >= u) break;
row_index = c.var();
const mpq & a = c.coeff();
unsigned i = lcs.m_r_basis[row_index];
impq const & xi = get_value(i);
#define SET_BOUND(_fn_, a, b, x, y, z) \
if (x.is_one()) \
_fn_(a, b, y - z); \
else if (x.is_minus_one()) \
_fn_(a, b, z - y); \
else if (z == y) \
_fn_(a, b, zero_of_type<impq>()); \
else \
{ _fn_(a, b, (y - z)/x); } \
if (a.is_neg()) {
if (has_low(i))
set_lower(l, inf_l, xj + (xi - lcs.m_r_lower_bounds()[i]) / a);
if (has_upper(i))
set_upper(u, inf_u, xj + (xi - lcs.m_r_upper_bounds()[i]) / a);
if (has_low(i)) {
SET_BOUND(set_lower, l, inf_l, a, xi, lcs.m_r_lower_bounds()[i]);
}
if (has_upper(i)) {
SET_BOUND(set_upper, u, inf_u, a, xi, lcs.m_r_upper_bounds()[i]);
}
}
else {
if (has_upper(i))
set_lower(l, inf_l, xj + (xi - lcs.m_r_upper_bounds()[i]) / a);
if (has_low(i))
set_upper(u, inf_u, xj + (xi - lcs.m_r_lower_bounds()[i]) / a);
if (has_upper(i)) {
SET_BOUND(set_lower, l, inf_l, a, xi, lcs.m_r_upper_bounds()[i]);
}
if (has_low(i)) {
SET_BOUND(set_upper, u, inf_u, a, xi, lcs.m_r_lower_bounds()[i]);
}
}
if (!inf_l && !inf_u && l >= u) break;
++rounds;
// patch always fails in this case
if (!inf_l && !inf_u && rounds > 2 && u - l < m && (xj.x + u.x) % m > (xj.x + l.x) % m) break;
}
l += xj;
u += xj;
TRACE("freedom_interval",
tout << "freedom variable for:\n";
tout << m_lar_solver->get_variable_name(j);