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propagate cheap eqs

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2020-06-02 12:38:31 -07:00
parent 865dfe0590
commit 1e4e887221
5 changed files with 78 additions and 82 deletions
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62
src/math/lp/bound_analyzer_on_row.h
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@ -13,9 +13,8 @@ Abstract:
In the same loop trying to pin variables by pushing the partial sum up, denoting the variable related to it by _l
Author:
Lev Nachmanson (levnach)
Lev Nachmanson (levnach)
Nikolaj Bjorner (nbjorner)
Revision History:
@ -31,7 +30,7 @@ template <typename C, typename B> // C plays a role of a container, B - lp_bound
class bound_analyzer_on_row {
const C& m_row;
B & m_bp;
unsigned m_row_or_term_index;
unsigned m_row_index;
int m_column_of_u; // index of an unlimited from above monoid
// -1 means that such a value is not found, -2 means that at least two of such monoids were found
int m_column_of_l; // index of an unlimited from below monoid
@ -48,7 +47,7 @@ public :
:
m_row(it),
m_bp(bp),
m_row_or_term_index(row_or_term_index),
m_row_index(row_or_term_index),
m_column_of_u(-1),
m_column_of_l(-1),
m_rs(rs)
@ -62,7 +61,7 @@ public :
B & bp) {
bound_analyzer_on_row a(row, bj, rs, row_or_term_index, bp);
a.analyze();
// TBD: a.analyze_eq();
a.analyze_eq();
}
private:
@ -84,37 +83,6 @@ private:
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));
@ -327,7 +295,7 @@ private:
// }
void limit_j(unsigned j, const mpq& u, bool coeff_before_j_is_pos, bool is_lower_bound, bool strict){
m_bp.try_add_bound(u, j, is_lower_bound, coeff_before_j_is_pos, m_row_or_term_index, strict);
m_bp.try_add_bound(u, j, is_lower_bound, coeff_before_j_is_pos, m_row_index, strict);
}
void advance_u(unsigned j) {
@ -361,6 +329,24 @@ private:
}
}
void analyze_eq() {
unsigned x = UINT_MAX, y = UINT_MAX;
unsigned k = 0;
for (const auto& c : m_row) {
if (!m_bp.lp().column_is_fixed(c.var())) {
if (x == UINT_MAX && c.coeff().is_one())
x = k;
else if (y == UINT_MAX && c.coeff().is_minus_one())
y = k;
else
return;
}
k++;
}
if (x == UINT_MAX || y == UINT_MAX)
return;
m_bp.try_create_eq(x, y, m_row_index);
}
};
}