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add stub for cheap equality propagation

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-05-30 15:36:17 -07:00
parent 6a45c5d17c
commit d372af4782
13 changed files with 131 additions and 105 deletions
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50
src/math/lp/bound_analyzer_on_row.h
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@ -55,6 +55,17 @@ public :
m_rs(rs)
{}
static void analyze_row(const C & row,
unsigned bj, // basis column for the row
const numeric_pair<mpq>& rs,
unsigned row_or_term_index,
lp_bound_propagator & bp) {
bound_analyzer_on_row a(row, bj, rs, row_or_term_index, bp);
a.analyze();
// TBD: a.analyze_eq();
}
private:
void analyze() {
for (const auto & c : m_row) {
@ -73,6 +84,37 @@ public :
limit_all_monoids_from_above();
}
void analyze_eq() {
lpvar x = null_lpvar, y = null_lpvar;
for (const auto & c : m_row) {
if (m_bp.get_column_type(c.var()) == column_type::fixed)
continue;
if (x == null_lpvar && c.coeff().is_one())
x = c.var();
else if (y == null_lpvar && c.coeff().is_minus_one())
y = c.var();
else
return;
}
if (x == null_lpvar || y == null_lpvar)
return;
impq value;
for (const auto & c : m_row) {
if (m_bp.get_column_type(c.var()) == column_type::fixed)
value += c.coeff() * lb(c.var());
}
if (!value.is_zero()) {
// insert / check offset table to infer equalities
// of the form y = z from offset table collision:
// value = (x - y)
// value = (x - z)
}
else {
// m_bp.try_add_fixed(x, y, m_row_or_term_index);
}
}
bool bound_is_available(unsigned j, bool lower_bound) {
return (lower_bound && lower_bound_is_available(j)) ||
(!lower_bound && upper_bound_is_available(j));
@ -319,14 +361,6 @@ public :
}
}
static void analyze_row(const C & row,
unsigned bj, // basis column for the row
const numeric_pair<mpq>& rs,
unsigned row_or_term_index,
lp_bound_propagator & bp) {
bound_analyzer_on_row a(row, bj, rs, row_or_term_index, bp);
a.analyze();
}
};
}