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patching merge (#6780)

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* patching merge

* fix the format and some warnings

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

* a fix in the delta calculation

* test patching

* try a new version of get_patching_deltas

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

* remove dead code from lp_tst and try optimizing patching

* add comments, replace VERIFY with lp_assert

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

* cleanup

---------

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2023-06-27 17:53:27 -07:00 • committed by GitHub
parent b2c035ea3f
commit 30a2ced9aa
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13 changed files with 1989 additions and 1800 deletions
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4
src/math/lp/.clang-format Normal file
View file

@ -0,0 +1,4 @@
BasedOnStyle: Google
IndentWidth: 4
ColumnLimit: 0
NamespaceIndentation: All

9
src/math/lp/explanation.h
View file

@ -49,6 +49,15 @@ public:
m_set.insert(j);
}
void remove(constraint_index j) {
m_set.remove(j);
unsigned i = 0;
for (auto& p : m_vector)
if (p.first != j)
m_vector[i++] = p;
m_vector.shrink(i);
}
void add_expl(const explanation& e) {
if (e.m_vector.empty()) {
for (constraint_index j : e.m_set)

370
src/math/lp/int_solver.cpp
View file

@ -2,8 +2,7 @@
Copyright (c) 2017 Microsoft Corporation
Author: Lev Nachmanson
*/
#include <utility>
// clang-format off
#include "math/lp/int_solver.h"
#include "math/lp/lar_solver.h"
#include "math/lp/lp_utils.h"
@ -17,51 +16,211 @@ namespace lp {
int_solver::patcher::patcher(int_solver& lia):
lia(lia),
lra(lia.lra),
lrac(lia.lrac),
m_num_nbasic_patches(0),
m_patch_cost(0),
m_next_patch(0),
m_delay(0)
lrac(lia.lrac)
{}
bool int_solver::patcher::should_apply() {
#if 1
return true;
#else
if (m_delay == 0) {
return true;
void int_solver::patcher::remove_fixed_vars_from_base() {
unsigned num = lra.A_r().column_count();
for (unsigned v = 0; v < num; v++) {
if (!lia.is_base(v) || !lia.is_fixed(v))
continue;
auto const & r = lra.basic2row(v);
for (auto const& c : r) {
if (c.var() != v && !lia.is_fixed(c.var())) {
lra.pivot(c.var(), v);
break;
}
}
}
--m_delay;
return false;
#endif
}
lia_move int_solver::patcher::operator()() {
return patch_nbasic_columns();
unsigned int_solver::patcher::count_non_int() {
unsigned non_int = 0;
for (auto j : lra.r_basis())
if (lra.column_is_int(j) && !lra.column_value_is_int(j))
++non_int;
return non_int;
}
lia_move int_solver::patcher::patch_basic_columns() {
remove_fixed_vars_from_base();
lia.settings().stats().m_patches++;
lp_assert(lia.is_feasible());
// unsigned non_int_before, non_int_after;
// non_int_before = count_non_int();
// unsigned num = lra.A_r().column_count();
for (unsigned j : lra.r_basis())
if (!lra.get_value(j).is_int())
patch_basic_column(j);
// non_int_after = count_non_int();
// verbose_stream() << non_int_before << " -> " << non_int_after << "\n";
if (!lia.has_inf_int()) {
lia.settings().stats().m_patches_success++;
return lia_move::sat;
}
return lia_move::undef;
}
// clang-format on
/**
* \brief find integral and minimal, in the absolute values, deltas such that x - alpha*delta is integral too.
*/
bool get_patching_deltas(const rational& x, const rational& alpha,
rational& delta_0, rational& delta_1) {
auto a1 = numerator(alpha);
auto a2 = denominator(alpha);
auto x1 = numerator(x);
auto x2 = denominator(x);
if (!divides(x2, a2))
return false;
// delta has to be integral.
// We need to find delta such that x1/x2 + (a1/a2)*delta is integral (we are going to flip the delta sign later).
// Then a2*x1/x2 + a1*delta is integral, but x2 and x1 are coprime:
// that means that t = a2/x2 is
// integral. We established that a2 = x2*t Then x1 + a1*delta*(x2/a2) = x1
// + a1*(delta/t) is integral. Taking into account that t and a1 are
// coprime we have delta = t*k, where k is an integer.
rational t = a2 / x2;
// std::cout << "t = " << t << std::endl;
// Now we have x1/x2 + (a1/x2)*k is integral, or (x1 + a1*k)/x2 is integral.
// It is equivalent to x1 + a1*k = x2*m, where m is an integer
// We know that a2 and a1 are coprime, and x2 divides a2, so x2 and a1 are
// coprime. We can find u and v such that u*a1 + v*x2 = 1.
rational u, v;
gcd(a1, x2, u, v);
lp_assert(gcd(a1, x2, u, v).is_one());
// std::cout << "u = " << u << ", v = " << v << std::endl;
// std::cout << "x= " << (x1 / x2) << std::endl;
// std::cout << "x + (a1 / a2) * (-u * t) * x1 = "
// << x + (a1 / a2) * (-u * t) * x1 << std::endl;
lp_assert((x + (a1 / a2) * (-u * t) * x1).is_int());
// 1 = (u- l*x2 ) * a1 + (v + l*a1)*x2, for every integer l.
rational l_low, l_high;
auto sign = u.is_pos() ? 1 : -1;
auto p = sign * floor(abs(u / x2));
auto p_ = p + sign;
lp_assert(p * x2 <= u && u <= p_ * x2 || p * x2 >= u && u >= p_ * x2);
// std::cout << "u = " << u << ", v = " << v << std::endl;
// std::cout << "p = " << p << ", p_ = " << p_ << std::endl;
// std::cout << "u - p*x2 = " << u - p * x2 << ", u - p_*x2 = " << u - p_ * x2
// << std::endl;
mpq d_0 = (u - p * x2) * t * x1;
mpq d_1 = (u - p_ * x2) * t * x1;
if (abs(d_0) < abs(d_1)) {
delta_0 = d_0;
delta_1 = d_1;
} else {
delta_0 = d_1;
delta_1 = d_0;
}
return true;
// std::cout << "delta_0 = " << delta_0 << std::endl;
// std::cout << "delta_1 = " << delta_1 << std::endl;
}
// clang-format off
/**
* \brief try to patch the basic column v
*/
bool int_solver::patcher::patch_basic_column_on_row_cell(unsigned v, row_cell<mpq> const& c) {
if (v == c.var())
return false;
if (!lra.column_is_int(c.var())) // could use real to patch integer
return false;
if (c.coeff().is_int())
return false;
mpq a = fractional_part(c.coeff());
mpq r = fractional_part(lra.get_value(v));
lp_assert(0 < r && r < 1);
lp_assert(0 < a && a < 1);
mpq delta_0, delta_1;
if (!get_patching_deltas(r, a, delta_0, delta_1))
return false;
if (try_patch_column(v, c.var(), delta_0))
return true;
if (try_patch_column(v, c.var(), delta_1))
return true;
return false;
}
bool int_solver::patcher::try_patch_column(unsigned v, unsigned j, mpq const& delta) {
const auto & A = lra.A_r();
if (delta < 0) {
if (lia.has_lower(j) && lia.get_value(j) + impq(delta) < lra.get_lower_bound(j))
return false;
}
else {
if (lia.has_upper(j) && lia.get_value(j) + impq(delta) > lra.get_upper_bound(j))
return false;
}
for (auto const& c : A.column(j)) {
unsigned row_index = c.var();
unsigned i = lrac.m_r_basis[row_index];
auto old_val = lia.get_value(i);
auto new_val = old_val - impq(c.coeff()*delta);
if (lia.has_lower(i) && new_val < lra.get_lower_bound(i))
return false;
if (lia.has_upper(i) && new_val > lra.get_upper_bound(i))
return false;
if (old_val.is_int() && !new_val.is_int()){
return false; // do not waste resources on this case
}
lp_assert(i != v || new_val.is_int())
}
lra.set_value_for_nbasic_column(j, lia.get_value(j) + impq(delta));
return true;
}
void int_solver::patcher::patch_basic_column(unsigned v) {
SASSERT(!lia.is_fixed(v));
for (auto const& c : lra.basic2row(v))
if (patch_basic_column_on_row_cell(v, c))
return;
}
lia_move int_solver::patcher::patch_nbasic_columns() {
remove_fixed_vars_from_base();
lia.settings().stats().m_patches++;
lp_assert(lia.is_feasible());
m_num_nbasic_patches = 0;
m_patch_cost = 0;
for (unsigned j : lia.lrac.m_r_nbasis) {
patch_nbasic_column(j);
m_patch_success = 0;
m_patch_fail = 0;
m_num_ones = 0;
m_num_divides = 0;
//unsigned non_int_before = count_non_int();
unsigned num = lra.A_r().column_count();
for (unsigned v = 0; v < num; v++) {
if (lia.is_base(v))
continue;
patch_nbasic_column(v);
}
unsigned num_fixed = 0;
for (unsigned v = 0; v < num; v++)
if (lia.is_fixed(v))
++num_fixed;
lp_assert(lia.is_feasible());
//verbose_stream() << "patch " << m_patch_success << " fails " << m_patch_fail << " ones " << m_num_ones << " divides " << m_num_divides << " num fixed " << num_fixed << "\n";
//lra.display(verbose_stream());
//exit(0);
//unsigned non_int_after = count_non_int();
// verbose_stream() << non_int_before << " -> " << non_int_after << "\n";
if (!lia.has_inf_int()) {
lia.settings().stats().m_patches_success++;
m_delay = 0;
m_next_patch = 0;
return lia_move::sat;
}
if (m_patch_cost > 0 && m_num_nbasic_patches * 10 < m_patch_cost) {
m_delay = std::min(20u, m_next_patch++);
}
else {
m_delay = 0;
m_next_patch = 0;
}
return lia_move::undef;
}
@ -71,17 +230,48 @@ void int_solver::patcher::patch_nbasic_column(unsigned j) {
impq l, u;
mpq m;
bool has_free = lia.get_freedom_interval_for_column(j, inf_l, l, inf_u, u, m);
m_patch_cost += lra.A_r().number_of_non_zeroes_in_column(j);
if (!has_free) {
if (!has_free)
return;
}
bool m_is_one = m.is_one();
bool val_is_int = lia.value_is_int(j);
#if 0
const auto & A = lra.A_r();
#endif
// check whether value of j is already a multiple of m.
if (val_is_int && (m_is_one || (val.x / m).is_int())) {
if (m_is_one)
++m_num_ones;
else
++m_num_divides;
#if 0
for (auto c : A.column(j)) {
unsigned row_index = c.var();
unsigned i = lrac.m_r_basis[row_index];
if (!lia.get_value(i).is_int() ||
(lia.has_lower(i) && lia.get_value(i) < lra.get_lower_bound(i)) ||
(lia.has_upper(i) && lia.get_value(i) > lra.get_upper_bound(i))) {
verbose_stream() << "skip " << j << " " << m << ": ";
lia.display_row(verbose_stream(), A.m_rows[row_index]);
verbose_stream() << "\n";
}
}
#endif
return;
}
#if 0
if (!m_is_one) {
// lia.display_column(verbose_stream(), j);
for (auto c : A.column(j)) {
continue;
unsigned row_index = c.var();
lia.display_row(verbose_stream(), A.m_rows[row_index]);
verbose_stream() << "\n";
}
}
#endif
TRACE("patch_int",
tout << "TARGET j" << j << " -> [";
if (inf_l) tout << "-oo"; else tout << l;
@ -89,9 +279,33 @@ void int_solver::patcher::patch_nbasic_column(unsigned j) {
if (inf_u) tout << "oo"; else tout << u;
tout << "]";
tout << ", m: " << m << ", val: " << val << ", is_int: " << lra.column_is_int(j) << "\n";);
#if 0
verbose_stream() << "path " << m << " ";
if (!inf_l) verbose_stream() << "infl " << l.x << " ";
if (!inf_u) verbose_stream() << "infu " << u.x << " ";
verbose_stream() << "\n";
if (m.is_big() || (!inf_l && l.x.is_big()) || (!inf_u && u.x.is_big())) {
return;
}
#endif
#if 0
verbose_stream() << "TARGET v" << j << " -> [";
if (inf_l) verbose_stream() << "-oo"; else verbose_stream() << ceil(l.x) << " " << l << "\n";
verbose_stream() << ", ";
if (inf_u) verbose_stream() << "oo"; else verbose_stream() << floor(u.x) << " " << u << "\n";
verbose_stream() << "]";
verbose_stream() << ", m: " << m << ", val: " << val << ", is_int: " << lra.column_is_int(j) << "\n";
#endif
#if 0
if (!inf_l)
l = impq(ceil(l));
if (!inf_u)
u = impq(floor(u));
#endif
if (!inf_l) {
l = impq(m_is_one ? ceil(l) : m * ceil(l / m));
if (inf_u || l <= u) {
@ -99,8 +313,23 @@ void int_solver::patcher::patch_nbasic_column(unsigned j) {
lra.set_value_for_nbasic_column(j, l);
}
else {
--m_num_nbasic_patches;
//verbose_stream() << "fail: " << j << " " << m << "\n";
++m_patch_fail;
TRACE("patch_int", tout << "not patching " << l << "\n";);
#if 0
verbose_stream() << "not patched\n";
for (auto c : A.column(j)) {
unsigned row_index = c.var();
unsigned i = lrac.m_r_basis[row_index];
if (!lia.get_value(i).is_int() ||
(lia.has_lower(i) && lia.get_value(i) < lra.get_lower_bound(i)) ||
(lia.has_upper(i) && lia.get_value(i) > lra.get_upper_bound(i))) {
lia.display_row(verbose_stream(), A.m_rows[row_index]);
verbose_stream() << "\n";
}
}
#endif
return;
}
}
else if (!inf_u) {
@ -112,7 +341,21 @@ void int_solver::patcher::patch_nbasic_column(unsigned j) {
lra.set_value_for_nbasic_column(j, impq(0));
TRACE("patch_int", tout << "patching with 0\n";);
}
++m_num_nbasic_patches;
++m_patch_success;
#if 0
verbose_stream() << "patched " << j << "\n";
for (auto c : A.column(j)) {
unsigned row_index = c.var();
unsigned i = lrac.m_r_basis[row_index];
if (!lia.get_value(i).is_int() ||
(lia.has_lower(i) && lia.get_value(i) < lra.get_lower_bound(i)) ||
(lia.has_upper(i) && lia.get_value(i) > lra.get_upper_bound(i))) {
lia.display_row(verbose_stream(), A.m_rows[row_index]);
verbose_stream() << "\n";
}
}
#endif
}
int_solver::int_solver(lar_solver& lar_slv) :
@ -326,7 +569,7 @@ static void set_upper(impq & u, bool & inf_u, impq const & v) {
// this function assumes that all basic columns dependend on j are feasible
bool int_solver::get_freedom_interval_for_column(unsigned j, bool & inf_l, impq & l, bool & inf_u, impq & u, mpq & m) {
if (lrac.m_r_heading[j] >= 0) // the basic var
if (lrac.m_r_heading[j] >= 0 || is_fixed(j)) // basic or fixed var
return false;
TRACE("random_update", display_column(tout, j) << ", is_int = " << column_is_int(j) << "\n";);
@ -361,10 +604,9 @@ bool int_solver::get_freedom_interval_for_column(unsigned j, bool & inf_l, impq
unsigned i = lrac.m_r_basis[row_index];
impq const & xi = get_value(i);
lp_assert(lrac.m_r_solver.column_is_feasible(i));
if (column_is_int(i) && !a.is_int())
if (column_is_int(i) && !a.is_int() && xi.is_int())
m = lcm(m, denominator(a));
if (!inf_l && !inf_u) {
if (l == u)
continue;
@ -372,15 +614,15 @@ bool int_solver::get_freedom_interval_for_column(unsigned j, bool & inf_l, impq
if (a.is_neg()) {
if (has_lower(i))
set_lower(l, inf_l, delta(a, xi, lrac.m_r_lower_bounds()[i]));
set_lower(l, inf_l, delta(a, xi, lra.get_lower_bound(i)));
if (has_upper(i))
set_upper(u, inf_u, delta(a, xi, lrac.m_r_upper_bounds()[i]));
set_upper(u, inf_u, delta(a, xi, lra.get_upper_bound(i)));
}
else {
if (has_upper(i))
set_lower(l, inf_l, delta(a, xi, lrac.m_r_upper_bounds()[i]));
set_lower(l, inf_l, delta(a, xi, lra.get_upper_bound(i)));
if (has_lower(i))
set_upper(u, inf_u, delta(a, xi, lrac.m_r_lower_bounds()[i]));
set_upper(u, inf_u, delta(a, xi, lra.get_lower_bound(i)));
}
}
@ -481,12 +723,9 @@ bool int_solver::at_upper(unsigned j) const {
std::ostream & int_solver::display_row(std::ostream & out, lp::row_strip<rational> const & row) const {
bool first = true;
auto & rslv = lrac.m_r_solver;
for (const auto &c : row)
{
if (is_fixed(c.var()))
{
if (!get_value(c.var()).is_zero())
{
for (const auto &c : row) {
if (is_fixed(c.var())) {
if (!get_value(c.var()).is_zero()) {
impq val = get_value(c.var()) * c.coeff();
if (!first && val.is_pos())
out << "+";
@ -505,17 +744,11 @@ for (const auto &c : row)
}
else if (c.coeff().is_minus_one())
out << "-";
else
{
if (c.coeff().is_pos())
{
if (!first)
else {
if (c.coeff().is_pos() && !first)
out << "+";
}
if (c.coeff().is_big())
{
out << " b*";
}
else
out << c.coeff();
}
@ -523,8 +756,7 @@ for (const auto &c : row)
first = false;
}
out << "\n";
for (const auto &c : row)
{
for (const auto &c : row) {
if (is_fixed(c.var()))
continue;
rslv.print_column_info(c.var(), out);
@ -533,14 +765,13 @@ for (const auto &c : row)
}
return out;
}
std::ostream& int_solver::display_row_info(std::ostream & out, unsigned row_index) const {
auto & rslv = lrac.m_r_solver;
auto const& row = rslv.m_A.m_rows[row_index];
return display_row(out, row);
}
bool int_solver::shift_var(unsigned j, unsigned range) {
if (is_fixed(j) || is_base(j))
return false;
@ -549,11 +780,13 @@ bool int_solver::shift_var(unsigned j, unsigned range) {
bool inf_l = false, inf_u = false;
impq l, u;
mpq m;
VERIFY(get_freedom_interval_for_column(j, inf_l, l, inf_u, u, m) || settings().get_cancel_flag());
if (!get_freedom_interval_for_column(j, inf_l, l, inf_u, u, m))
return false;
if (settings().get_cancel_flag())
return false;
const impq & x = get_value(j);
// x, the value of j column, might be shifted on a multiple of m
if (inf_l && inf_u) {
impq new_val = m * impq(random() % (range + 1)) + x;
lra.set_value_for_nbasic_column(j, new_val);
@ -570,6 +803,7 @@ bool int_solver::shift_var(unsigned j, unsigned range) {
if (!inf_l && !inf_u && l >= u)
return false;
if (inf_u) {
SASSERT(!inf_l);
impq new_val = x + m * impq(random() % (range + 1));
@ -640,9 +874,6 @@ int int_solver::select_int_infeasible_var() {
unsigned n = 0;
lar_core_solver & lcs = lra.m_mpq_lar_core_solver;
unsigned prev_usage = 0; // to quiet down the compile
unsigned k = 0;
unsigned usage;
unsigned j;
enum state { small_box, is_small_value, any_value, not_found };
state st = not_found;
@ -650,11 +881,10 @@ int int_solver::select_int_infeasible_var() {
// 1. small box
// 2. small value
// 3. any value
for (; k < lra.r_basis().size(); k++) {
j = lra.r_basis()[k];
for (unsigned j : lra.r_basis()) {
if (!column_is_int_inf(j))
continue;
usage = lra.usage_in_terms(j);
unsigned usage = lra.usage_in_terms(j);
if (is_boxed(j) && (new_range = lcs.m_r_upper_bounds()[j].x - lcs.m_r_lower_bounds()[j].x - rational(2*usage)) <= small_value) {
SASSERT(!is_fixed(j));
if (st != small_box) {
@ -688,12 +918,12 @@ int int_solver::select_int_infeasible_var() {
continue;
SASSERT(st == not_found || st == any_value);
st = any_value;
if (n == 0 /*|| usage > prev_usage*/) {
if (n == 0 || usage > prev_usage) {
result = j;
prev_usage = usage;
n = 1;
}
else if (usage > 0 && /*usage == prev_usage && */ (random() % (++n) == 0))
else if (usage > 0 && usage == prev_usage && (random() % (++n) == 0))
result = j;
}

19
src/math/lp/int_solver.h
View file

@ -17,6 +17,7 @@ Revision History:
--*/
// clang-format off
#pragma once
#include "math/lp/lp_settings.h"
#include "math/lp/static_matrix.h"
@ -44,17 +45,23 @@ class int_solver {
int_solver& lia;
lar_solver& lra;
lar_core_solver& lrac;
unsigned m_num_nbasic_patches;
unsigned m_patch_cost;
unsigned m_next_patch;
unsigned m_delay;
unsigned m_patch_success = 0;
unsigned m_patch_fail = 0;
unsigned m_num_ones = 0;
unsigned m_num_divides = 0;
public:
patcher(int_solver& lia);
bool should_apply();
lia_move operator()();
bool should_apply() const { return true; }
lia_move operator()() { return patch_basic_columns(); }
void patch_nbasic_column(unsigned j);
bool patch_basic_column_on_row_cell(unsigned v, row_cell<mpq> const& c);
void patch_basic_column(unsigned j);
bool try_patch_column(unsigned v, unsigned j, mpq const& delta);
unsigned count_non_int();
private:
void remove_fixed_vars_from_base();
lia_move patch_nbasic_columns();
lia_move patch_basic_columns();
};
lar_solver& lra;

2
src/math/lp/lar_core_solver.h
View file

@ -93,6 +93,8 @@ public:
void solve();
void pivot(int entering, int leaving) { m_r_solver.pivot(entering, leaving); }
bool lower_bounds_are_set() const { return true; }
const indexed_vector<mpq> & get_pivot_row() const {

76
src/math/lp/lar_solver.cpp
View file

@ -2,7 +2,7 @@
Copyright (c) 2017 Microsoft Corporation
Author: Nikolaj Bjorner, Lev Nachmanson
*/
// clang-format off
#include "math/lp/lar_solver.h"
#include "smt/params/smt_params_helper.hpp"
@ -42,7 +42,6 @@ namespace lp {
delete t;
}
bool lar_solver::sizes_are_correct() const {
lp_assert(A_r().column_count() == m_mpq_lar_core_solver.m_r_solver.m_column_types.size());
lp_assert(A_r().column_count() == m_mpq_lar_core_solver.m_r_solver.m_costs.size());
@ -50,7 +49,6 @@ namespace lp {
return true;
}
std::ostream& lar_solver::print_implied_bound(const implied_bound& be, std::ostream& out) const {
out << "implied bound\n";
unsigned v = be.m_j;
@ -1354,8 +1352,8 @@ namespace lp {
}
bool lar_solver::term_is_int(const vector<std::pair<mpq, unsigned int>>& coeffs) const {
for (auto const& p : coeffs)
if (!(column_is_int(p.second) && p.first.is_int()))
for (auto const& [coeff, v] : coeffs)
if (!(column_is_int(v) && coeff.is_int()))
return false;
return true;
}
@ -1386,7 +1384,7 @@ namespace lp {
// the lower/upper bound is not strict.
// the LP obtained by making the bound strict is infeasible
// -> the column has to be fixed
bool lar_solver::is_fixed_at_bound(column_index const& j) {
bool lar_solver::is_fixed_at_bound(column_index const& j, vector<std::tuple<explanation, column_index, bool, mpq>>& bounds) {
if (column_is_fixed(j))
return false;
mpq val;
@ -1395,50 +1393,56 @@ namespace lp {
lp::lconstraint_kind k;
if (column_has_upper_bound(j) &&
get_upper_bound(j).x == val) {
verbose_stream() << "check upper " << j << "\n";
push();
if (column_is_int(j))
k = LE, val -= 1;
else
k = LT;
auto ci = mk_var_bound(j, k, val);
update_column_type_and_bound(j, k, val, ci);
k = column_is_int(j) ? LE : LT;
auto ci = mk_var_bound(j, k, column_is_int(j) ? val - 1 : val);
update_column_type_and_bound(j, k, column_is_int(j) ? val - 1 : val, ci);
auto st = find_feasible_solution();
bool infeasible = st == lp_status::INFEASIBLE;
if (infeasible) {
explanation exp;
get_infeasibility_explanation(exp);
unsigned_vector cis;
exp.remove(ci);
verbose_stream() << "tight upper bound " << j << " " << val << "\n";
bounds.push_back({exp, j, true, val});
}
pop(1);
return st == lp_status::INFEASIBLE;
return infeasible;
}
if (column_has_lower_bound(j) &&
get_lower_bound(j).x == val) {
verbose_stream() << "check lower " << j << "\n";
push();
if (column_is_int(j))
k = GE, val += 1;
else
k = GT;
auto ci = mk_var_bound(j, k, val);
update_column_type_and_bound(j, k, val, ci);
k = column_is_int(j) ? GE : GT;
auto ci = mk_var_bound(j, k, column_is_int(j) ? val + 1 : val);
update_column_type_and_bound(j, k, column_is_int(j) ? val + 1 : val, ci);
auto st = find_feasible_solution();
bool infeasible = st == lp_status::INFEASIBLE;
if (infeasible) {
explanation exp;
get_infeasibility_explanation(exp);
exp.remove(ci);
verbose_stream() << "tight lower bound " << j << " " << val << "\n";
bounds.push_back({exp, j, false, val});
}
pop(1);
return st == lp_status::INFEASIBLE;
return infeasible;
}
return false;
}
bool lar_solver::has_fixed_at_bound() {
bool lar_solver::has_fixed_at_bound(vector<std::tuple<explanation, column_index, bool, mpq>>& bounds) {
verbose_stream() << "has-fixed-at-bound\n";
unsigned num_fixed = 0;
for (unsigned j = 0; j < A_r().m_columns.size(); ++j) {
auto ci = column_index(j);
if (is_fixed_at_bound(ci)) {
++num_fixed;
if (is_fixed_at_bound(ci, bounds))
verbose_stream() << "fixed " << j << "\n";
}
}
verbose_stream() << "num fixed " << num_fixed << "\n";
if (num_fixed > 0)
verbose_stream() << "num fixed " << bounds.size() << "\n";
if (!bounds.empty())
find_feasible_solution();
return num_fixed > 0;
return !bounds.empty();
}
@ -1617,6 +1621,18 @@ namespace lp {
return ret;
}
/**
* \brief ensure there is a column index corresponding to vi
* If vi is already a column, just return vi
* If vi is for a term, then create a row that uses the term.
*/
var_index lar_solver::ensure_column(var_index vi) {
if (lp::tv::is_term(vi))
return to_column(vi);
else
return vi;
}
void lar_solver::add_row_from_term_no_constraint(const lar_term* term, unsigned term_ext_index) {
TRACE("dump_terms", print_term(*term, tout) << std::endl;);

105
src/math/lp/lar_solver.h
View file

@ -18,29 +18,30 @@
--*/
#pragma once
#include "util/vector.h"
#include <utility>
#include "util/debug.h"
#include "util/buffer.h"
#include <algorithm>
#include <functional>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <string>
#include <algorithm>
#include <stack>
#include <functional>
#include <utility>
#include "math/lp/bound_analyzer_on_row.h"
#include "math/lp/implied_bound.h"
#include "math/lp/int_solver.h"
#include "math/lp/lar_constraints.h"
#include "math/lp/lar_core_solver.h"
#include "math/lp/numeric_pair.h"
#include "math/lp/lp_primal_core_solver.h"
#include "math/lp/random_updater.h"
#include "util/stacked_value.h"
#include "math/lp/stacked_vector.h"
#include "math/lp/implied_bound.h"
#include "math/lp/bound_analyzer_on_row.h"
#include "math/lp/int_solver.h"
#include "math/lp/nra_solver.h"
#include "math/lp/lp_types.h"
#include "math/lp/lp_bound_propagator.h"
#include "math/lp/lp_primal_core_solver.h"
#include "math/lp/lp_types.h"
#include "math/lp/nra_solver.h"
#include "math/lp/numeric_pair.h"
#include "math/lp/random_updater.h"
#include "math/lp/stacked_vector.h"
#include "util/buffer.h"
#include "util/debug.h"
#include "util/stacked_value.h"
#include "util/vector.h"
namespace lp {
@ -48,10 +49,9 @@ class int_branch;
class int_solver;
class lar_solver : public column_namer {
struct term_hasher {
std::size_t operator()(const lar_term &t) const
{
using std::size_t;
std::size_t operator()(const lar_term& t) const {
using std::hash;
using std::size_t;
using std::string;
size_t seed = 0;
int i = 0;
@ -66,8 +66,7 @@ class lar_solver : public column_namer {
};
struct term_comparer {
bool operator()(const lar_term &a, const lar_term& b) const
{
bool operator()(const lar_term& a, const lar_term& b) const {
return a == b;
}
};
@ -161,12 +160,10 @@ class lar_solver : public column_namer {
bool sizes_are_correct() const;
bool implied_bound_is_correctly_explained(implied_bound const& be, const vector<std::pair<mpq, unsigned>>& explanation) const;
void substitute_basis_var_in_terms_for_row(unsigned i);
template <typename T>
unsigned calculate_implied_bounds_for_row(unsigned row_index, lp_bound_propagator<T>& bp) {
if (A_r().m_rows[row_index].size() > settings().max_row_length_for_bound_propagation || row_has_a_big_num(row_index))
return 0;
@ -180,7 +177,6 @@ class lar_solver : public column_namer {
static void clean_popped_elements_for_heap(unsigned n, lpvar_heap& set);
static void clean_popped_elements(unsigned n, u_set& set);
bool maximize_term_on_tableau(const lar_term& term,
impq& term_max);
bool costs_are_zeros_for_r_solver() const;
@ -258,7 +254,6 @@ public:
return m_fixed_var_table_int;
}
const map<mpq, unsigned, obj_hash<mpq>, default_eq<mpq>>& fixed_var_table_real() const {
return m_fixed_var_table_real;
}
@ -271,7 +266,8 @@ public:
return is_int ? fixed_var_table_int().find(mpq, j) : fixed_var_table_real().find(mpq, j);
}
template <typename T> void remove_non_fixed_from_table(T&);
template <typename T>
void remove_non_fixed_from_table(T&);
unsigned external_to_column_index(unsigned) const;
@ -368,8 +364,8 @@ public:
}
}
bool is_fixed_at_bound(column_index const& j);
bool has_fixed_at_bound();
bool is_fixed_at_bound(column_index const& j, vector<std::tuple<explanation, column_index, bool, mpq>>& bounds);
bool has_fixed_at_bound(vector<std::tuple<explanation, column_index, bool, mpq>>& bounds);
bool is_fixed(column_index const& j) const { return column_is_fixed(j); }
inline column_index to_column_index(unsigned v) const { return column_index(external_to_column_index(v)); }
@ -378,6 +374,7 @@ public:
bool compare_values(var_index j, lconstraint_kind kind, const mpq& right_side);
var_index add_term(const vector<std::pair<mpq, var_index>>& coeffs, unsigned ext_i);
void register_existing_terms();
var_index ensure_column(var_index vi);
constraint_index add_var_bound(var_index, lconstraint_kind, const mpq&);
constraint_index add_var_bound_check_on_equal(var_index, lconstraint_kind, const mpq&, var_index&);
@ -385,34 +382,40 @@ public:
void set_cut_strategy(unsigned cut_frequency);
inline unsigned column_count() const { return A_r().column_count(); }
inline var_index local_to_external(var_index idx) const {
return tv::is_term(idx)?
m_term_register.local_to_external(idx) : m_var_register.local_to_external(idx);
return tv::is_term(idx) ? m_term_register.local_to_external(idx) : m_var_register.local_to_external(idx);
}
bool column_corresponds_to_term(unsigned) const;
const lar_term& column_to_term(unsigned j) const {
SASSERT(column_corresponds_to_term(j));
return get_term(column2tv(to_column_index(j)));
}
bool column_corresponds_to_term(unsigned) const;
inline unsigned row_count() const { return A_r().row_count(); }
bool var_is_registered(var_index vj) const;
void clear_inf_heap() {
m_mpq_lar_core_solver.m_r_solver.inf_heap().clear();
}
inline void remove_column_from_inf_heap(unsigned j) {
inline void remove_column_from_inf_set(unsigned j) {
m_mpq_lar_core_solver.m_r_solver.remove_column_from_inf_heap(j);
}
void pivot(int entering, int leaving) {
m_mpq_lar_core_solver.pivot(entering, leaving);
}
template <typename ChangeReport>
void change_basic_columns_dependend_on_a_given_nb_column_report(unsigned j,
const numeric_pair<mpq>& delta,
const ChangeReport& after) {
for (const auto& c : A_r().m_columns[j]) {
unsigned bj = m_mpq_lar_core_solver.m_r_basis[c.var()];
if (tableau_with_costs()) {
if (tableau_with_costs())
m_basic_columns_with_changed_cost.insert(bj);
}
m_mpq_lar_core_solver.m_r_solver.add_delta_to_x_and_track_feasibility(bj, -A_r().get_val(c) * delta);
after(bj);
TRACE("change_x_del",
tout << "changed basis column " << bj << ", it is " <<
( m_mpq_lar_core_solver.m_r_solver.column_is_feasible(bj)? "feas":"inf") << std::endl;);
tout << "changed basis column " << bj << ", it is " << (m_mpq_lar_core_solver.m_r_solver.column_is_feasible(bj) ? "feas" : "inf") << std::endl;);
}
}
@ -420,7 +423,6 @@ public:
void set_value_for_nbasic_column_report(unsigned j,
const impq& new_val,
const ChangeReport& after) {
lp_assert(!is_base(j));
auto& x = m_mpq_lar_core_solver.m_r_x[j];
auto delta = new_val - x;
@ -465,21 +467,18 @@ public:
return m_mpq_lar_core_solver.m_r_solver.column_has_lower_bound(j);
}
inline
constraint_index get_column_upper_bound_witness(unsigned j) const {
inline constraint_index get_column_upper_bound_witness(unsigned j) const {
if (tv::is_term(j)) {
j = m_var_register.external_to_local(j);
}
return m_columns_to_ul_pairs()[j].upper_bound_witness();
}
inline
const impq& get_upper_bound(column_index j) const {
inline const impq& get_upper_bound(column_index j) const {
return m_mpq_lar_core_solver.m_r_solver.m_upper_bounds[j];
}
inline
const impq& get_lower_bound(column_index j) const {
inline const impq& get_lower_bound(column_index j) const {
return m_mpq_lar_core_solver.m_r_solver.m_lower_bounds[j];
}
bool has_lower_bound(var_index var, constraint_index& ci, mpq& value, bool& is_strict) const;
@ -586,7 +585,10 @@ public:
inline void set_int_solver(int_solver* int_slv) { m_int_solver = int_slv; }
inline int_solver* get_int_solver() { return m_int_solver; }
inline const int_solver* get_int_solver() const { return m_int_solver; }
inline const lar_term & get_term(tv const& t) const { lp_assert(t.is_term()); return *m_terms[t.id()]; }
inline const lar_term& get_term(tv const& t) const {
lp_assert(t.is_term());
return *m_terms[t.id()];
}
lp_status find_feasible_solution();
void move_non_basic_columns_to_bounds(bool);
bool move_non_basic_column_to_bounds(unsigned j, bool);
@ -629,14 +631,12 @@ public:
bool column_is_int(column_index const& j) const { return column_is_int((unsigned)j); }
// const impq& get_ivalue(column_index const& j) const { return get_column_value(j); }
const impq& get_column_value(column_index const& j) const { return m_mpq_lar_core_solver.m_r_x[j]; }
inline
var_index external_to_local(unsigned j) const {
inline var_index external_to_local(unsigned j) const {
var_index local_j;
if (m_var_register.external_is_used(j, local_j) ||
m_term_register.external_is_used(j, local_j)) {
return local_j;
}
else {
} else {
return -1;
}
}
@ -647,6 +647,5 @@ public:
}
friend int_solver;
friend int_branch;
};
}
} // namespace lp

95
src/math/lp/lp_bound_propagator.h
View file

@ -4,20 +4,23 @@
Nikolaj Bjorner (nbjorner)
Lev Nachmanson (levnach)
*/
//clang-format off
#pragma once
#include "math/lp/lp_settings.h"
#include <utility>
#include "math/lp/lp_settings.h"
#include "util/uint_set.h"
namespace lp {
template <typename T>
class lp_bound_propagator {
class edge; // forward definition
// vertex represents a column
// The set of vertices is organised in a tree.
// The set of vertices is organized in a tree.
// The edges of the tree are rows,
// Vertices with m_neg set to false grow with the same rate as the root.
// Vertices with m_neq set to true diminish with the same rate as the roow grows.
// When two vertices with the same m_neg have the same value of columns
// then we have an equality betweet the columns.
// then we have an equality between the columns.
class vertex {
unsigned m_column;
vector<edge> m_edges;
@ -26,10 +29,8 @@ class lp_bound_propagator {
// it is handy to find the common ancestor
public:
vertex() {}
vertex(unsigned column) :
m_column(column),
m_level(0)
{}
vertex(unsigned column) : m_column(column),
m_level(0) {}
unsigned column() const { return m_column; }
const vertex* parent() const { return m_edge_from_parent.source(); }
vertex* parent() { return m_edge_from_parent.source(); }
@ -58,6 +59,7 @@ class lp_bound_propagator {
vertex* m_source;
vertex* m_target;
int m_row;
public:
edge(vertex* source, vertex* target, int row) : m_source(source), m_target(target), m_row(row) {}
edge() : m_source(nullptr), m_target(nullptr), m_row(-1) {}
@ -69,7 +71,10 @@ class lp_bound_propagator {
edge reverse() const { return edge(m_target, m_source, m_row); }
};
static int other(int x, int y, int z) { SASSERT(x == z || y == z); return x == z ? y : x; }
static int other(int x, int y, int z) {
SASSERT(x == z || y == z);
return x == z ? y : x;
}
std::ostream& print_vert(std::ostream& out, const vertex* v) const {
out << "(c = " << v->column() << ", parent = {";
if (v->parent())
@ -113,8 +118,6 @@ class lp_bound_propagator {
T& m_imp;
vector<implied_bound> m_ibounds;
map<mpq, unsigned, obj_hash<mpq>, default_eq<mpq>> m_val2fixed_row;
bool is_fixed_row(unsigned r, unsigned& x) {
@ -165,7 +168,8 @@ class lp_bound_propagator {
}
TRACE("cheap_eq",
tout << "v_j = "; lp().print_column_info(v_j, tout) << std::endl;
tout << "v_j = ";
lp().print_column_info(v_j, tout) << std::endl;
tout << "v = "; print_vert(tout, v) << std::endl;
tout << "found j " << j << std::endl; lp().print_column_info(j, tout) << std::endl;
tout << "found j = " << j << std::endl;);
@ -214,8 +218,7 @@ class lp_bound_propagator {
if (not_set(y)) {
set_fixed_vertex(m_root);
explain_fixed_in_row(row_index, m_fixed_vertex_explanation);
}
else {
} else {
vertex* v = add_child_with_check(row_index, y, m_root, polarity);
if (v)
explore_under(v);
@ -243,19 +246,15 @@ class lp_bound_propagator {
if (c.coeff().is_one() || c.coeff().is_minus_one()) {
x = c.var();
x_cell = &c;
}
else
} else
return false;
}
else if (not_set(y)) {
} else if (not_set(y)) {
if (c.coeff().is_one() || c.coeff().is_minus_one()) {
y = c.var();
y_cell = &c;
}
else
} else
return false;
}
else
} else
return false;
}
if (is_set(x)) {
@ -302,11 +301,8 @@ class lp_bound_propagator {
~reset_cheap_eq() { p.reset_cheap_eq_eh(); }
};
public:
lp_bound_propagator(T& imp):
m_imp(imp) {}
lp_bound_propagator(T& imp) : m_imp(imp) {}
const vector<implied_bound>& ibounds() const { return m_ibounds; }
@ -361,22 +357,19 @@ public:
found_bound = implied_bound(v, j, is_low, coeff_before_j_is_pos, row_or_term_index, strict);
TRACE("try_add_bound", m_imp.lp().print_implied_bound(found_bound, tout););
}
}
else {
} else {
m_improved_lower_bounds[j] = m_ibounds.size();
m_ibounds.push_back(implied_bound(v, j, is_low, coeff_before_j_is_pos, row_or_term_index, strict));
TRACE("try_add_bound", m_imp.lp().print_implied_bound(m_ibounds.back(), tout););
}
}
else { // the upper bound case
} else { // the upper bound case
if (try_get_value(m_improved_upper_bounds, j, k)) {
auto& found_bound = m_ibounds[k];
if (v < found_bound.m_bound || (v == found_bound.m_bound && !found_bound.m_strict && strict)) {
found_bound = implied_bound(v, j, is_low, coeff_before_j_is_pos, row_or_term_index, strict);
TRACE("try_add_bound", m_imp.lp().print_implied_bound(found_bound, tout););
}
}
else {
} else {
m_improved_upper_bounds[j] = m_ibounds.size();
m_ibounds.push_back(implied_bound(v, j, is_low, coeff_before_j_is_pos, row_or_term_index, strict));
TRACE("try_add_bound", m_imp.lp().print_implied_bound(m_ibounds.back(), tout););
@ -430,10 +423,14 @@ public:
explain_fixed_in_row(row_index, m_fixed_vertex_explanation);
set_fixed_vertex(v);
TRACE("cheap_eq",
tout << "polarity switch: " << polarity << "\nv = "; print_vert(tout , v) << "\nu = "; tout << "fixed vertex explanation\n";
for (auto p : m_fixed_vertex_explanation)
lp().constraints().display(tout, [this](lpvar j) { return lp().get_variable_name(j);}, p.ci()););
tout << "polarity switch: " << polarity << "\nv = ";
print_vert(tout, v) << "\nu = "; tout << "fixed vertex explanation\n";
for (auto p
: m_fixed_vertex_explanation)
lp()
.constraints()
.display(
tout, [this](lpvar j) { return lp().get_variable_name(j); }, p.ci()););
}
bool tree_contains(vertex* v) const {
@ -449,19 +446,18 @@ public:
return v;
}
unsigned column(unsigned row, unsigned index) {
return lp().get_row(row)[index].var();
}
bool fixed_phase() const { return m_fixed_vertex; }
// Returns the vertex to start exploration from, or nullptr.
// It is assumed that parent->column() is present in the row
vertex* get_child_from_row(unsigned row_index, vertex* parent) {
TRACE("cheap_eq_det", print_row(tout, row_index););
unsigned x, y; int row_polarity;
unsigned x, y;
int row_polarity;
if (!is_tree_offset_row(row_index, x, y, row_polarity)) {
TRACE("cheap_eq_det", tout << "not an offset row\n";);
return nullptr;
@ -508,12 +504,10 @@ public:
is_int(k->column()) == is_int(v->column()) &&
!is_equal(k->column(), v->column())) {
report_eq(k, v);
}
else {
} else {
TRACE("cheap_eq", tout << "no report\n";);
}
}
else {
} else {
TRACE("cheap_eq", tout << "registered: " << val(v) << " -> { "; print_vert(tout, v) << "} \n";);
table.insert(val(v), v);
}
@ -557,12 +551,12 @@ public:
vector<edge> path = connect_in_tree(v_i, v_j);
lp::explanation exp = get_explanation_from_path(path);
add_eq_on_columns(exp, v_i->column(), v_j->column(), false);
}
std::ostream& print_expl(std::ostream& out, const explanation& exp) const {
for (auto p : exp)
lp().constraints().display(out, [this](lpvar j) { return lp().get_variable_name(j);}, p.ci());
lp().constraints().display(
out, [this](lpvar j) { return lp().get_variable_name(j); }, p.ci());
return out;
}
@ -574,8 +568,7 @@ public:
tout << "reporting eq " << j << ", " << k << "\n";
tout << "reported idx " << je << ", " << ke << "\n";
print_expl(tout, exp);
tout << "theory_vars v" << lp().local_to_external(je) << " == v" << lp().local_to_external(ke) << "\n";
);
tout << "theory_vars v" << lp().local_to_external(je) << " == v" << lp().local_to_external(ke) << "\n";);
bool added = m_imp.add_eq(je, ke, exp, is_fixed);
if (added) {
@ -693,7 +686,6 @@ public:
try_add_equation_with_fixed_tables(row_index, e.target());
}
void cheap_eq_tree(unsigned row_index) {
reset_cheap_eq _reset(*this);
TRACE("cheap_eq_det", tout << "row_index = " << row_index << "\n";);
@ -713,7 +705,8 @@ public:
}
std::ostream& print_row(std::ostream& out, unsigned row_index) const {
unsigned x, y; int polarity;
unsigned x, y;
int polarity;
if (true || !is_tree_offset_row(row_index, x, y, polarity))
return lp().get_int_solver()->display_row_info(out, row_index);
@ -724,8 +717,7 @@ public:
if (c.coeff().is_one()) {
if (!first)
out << "+";
}
else if (c.coeff().is_minus_one())
} else if (c.coeff().is_minus_one())
out << "-";
out << lp().get_variable_name(c.var()) << " ";
first = false;
@ -764,6 +756,5 @@ public:
table.insert(j);
return true;
}
};
}
} // namespace lp

75
src/math/lp/lp_primal_core_solver.h
View file

@ -17,7 +17,7 @@ Revision History:
--*/
// clang-format off
#pragma once
#include "math/lp/core_solver_pretty_printer.h"
#include "math/lp/lp_core_solver_base.h"
@ -98,22 +98,12 @@ public:
case column_type::fixed:
return false;
case column_type::lower_bound:
if (is_pos(rc.coeff())) {
return this->x_above_lower_bound(j);
}
return true;
return !is_pos(rc.coeff()) || this->x_above_lower_bound(j);
case column_type::upper_bound:
if (is_pos(rc.coeff())) {
return true;
}
return this->x_below_upper_bound(j);
return is_pos(rc.coeff()) || this->x_below_upper_bound(j);
case column_type::boxed:
if (is_pos(rc.coeff())) {
if (is_pos(rc.coeff()))
return this->x_above_lower_bound(j);
}
return this->x_below_upper_bound(j);
default:
return false;
@ -131,22 +121,16 @@ public:
case column_type::fixed:
return false;
case column_type::lower_bound:
if (is_neg(rc.coeff())) {
if (is_neg(rc.coeff()))
return this->x_above_lower_bound(j);
}
return true;
case column_type::upper_bound:
if (is_neg(rc.coeff())) {
if (is_neg(rc.coeff()))
return true;
}
return this->x_below_upper_bound(j);
case column_type::boxed:
if (is_neg(rc.coeff())) {
if (is_neg(rc.coeff()))
return this->x_above_lower_bound(j);
}
return this->x_below_upper_bound(j);
default:
return false;
@ -154,6 +138,7 @@ public:
UNREACHABLE(); // unreachable
return false;
}
/**
* Return the number of base non-free variables depending on the column j,
* different from bj,
@ -174,7 +159,7 @@ public:
}
return r;
}
// clang-format on
int find_beneficial_entering_in_row_tableau_rows_bland_mode(int i, T &a_ent) {
int j = -1;
unsigned bj = this->m_basis[i];
@ -194,13 +179,11 @@ public:
a_ent = rc.coeff();
}
}
if (j == -1) {
if (j == -1)
m_inf_row_index_for_tableau = i;
}
return j;
}
//clang-format off
int find_beneficial_entering_tableau_rows(int i, T &a_ent) {
if (m_bland_mode_tableau)
return find_beneficial_entering_in_row_tableau_rows_bland_mode(i, a_ent);
@ -248,54 +231,48 @@ public:
return rc.var();
}
bool try_jump_to_another_bound_on_entering(unsigned entering, const X &theta,
X &t, bool &unlimited);
bool try_jump_to_another_bound_on_entering(unsigned entering, const X &theta, X &t, bool &unlimited);
bool try_jump_to_another_bound_on_entering_unlimited(unsigned entering, X &t);
int find_leaving_and_t_tableau(unsigned entering, X &t);
void limit_theta(const X &lim, X &theta, bool &unlimited) {
if (unlimited) {
theta = lim;
unlimited = false;
} else {
} else
theta = std::min(lim, theta);
}
}
void limit_theta_on_basis_column_for_inf_case_m_neg_upper_bound(
unsigned j, const T &m, X &theta, bool &unlimited) {
lp_assert(m < 0 && this->m_column_types[j] == column_type::upper_bound);
limit_inf_on_upper_bound_m_neg(m, this->m_x[j], this->m_upper_bounds[j],
theta, unlimited);
limit_inf_on_upper_bound_m_neg(m, this->m_x[j], this->m_upper_bounds[j], theta, unlimited);
}
void limit_theta_on_basis_column_for_inf_case_m_neg_lower_bound(
unsigned j, const T &m, X &theta, bool &unlimited) {
lp_assert(m < 0 && this->m_column_types[j] == column_type::lower_bound);
limit_inf_on_bound_m_neg(m, this->m_x[j], this->m_lower_bounds[j], theta,
unlimited);
limit_inf_on_bound_m_neg(m, this->m_x[j], this->m_lower_bounds[j], theta, unlimited);
}
void limit_theta_on_basis_column_for_inf_case_m_pos_lower_bound(
unsigned j, const T &m, X &theta, bool &unlimited) {
lp_assert(m > 0 && this->m_column_types[j] == column_type::lower_bound);
limit_inf_on_lower_bound_m_pos(m, this->m_x[j], this->m_lower_bounds[j],
theta, unlimited);
limit_inf_on_lower_bound_m_pos(m, this->m_x[j], this->m_lower_bounds[j], theta, unlimited);
}
void limit_theta_on_basis_column_for_inf_case_m_pos_upper_bound(
unsigned j, const T &m, X &theta, bool &unlimited) {
lp_assert(m > 0 && this->m_column_types[j] == column_type::upper_bound);
limit_inf_on_bound_m_pos(m, this->m_x[j], this->m_upper_bounds[j], theta,
unlimited);
limit_inf_on_bound_m_pos(m, this->m_x[j], this->m_upper_bounds[j], theta, unlimited);
};
void get_bound_on_variable_and_update_leaving_precisely(
unsigned j, vector<unsigned> &leavings, T m, X &t,
T &abs_of_d_of_leaving);
#ifdef Z3DEBUG
void check_Ax_equal_b();
void check_the_bounds();
@ -303,12 +280,16 @@ public:
void check_correctness();
#endif
void backup_and_normalize_costs();
void advance_on_entering_and_leaving_tableau(int entering, int leaving, X &t);
void advance_on_entering_equal_leaving_tableau(int entering, X &t);
void pivot(int entering, int leaving) {
this->pivot_column_tableau(entering, this->m_basis_heading[leaving]);
this->change_basis(entering, leaving);
}
bool need_to_switch_costs() const {
if (this->m_settings.simplex_strategy() ==
simplex_strategy_enum::tableau_rows)
@ -338,13 +319,11 @@ public:
void update_x_tableau_rows(unsigned entering, unsigned leaving,
const X &delta) {
this->add_delta_to_x(entering, delta);
for (const auto &c : this->m_A.m_columns[entering]) {
if (leaving != this->m_basis[c.var()]) {
for (const auto &c : this->m_A.m_columns[entering])
if (leaving != this->m_basis[c.var()])
this->add_delta_to_x_and_track_feasibility(
this->m_basis[c.var()], -delta * this->m_A.get_val(c));
}
}
}
void update_basis_and_x_tableau_rows(int entering, int leaving, X const &tt) {
lp_assert(entering != leaving);
@ -365,8 +344,6 @@ public:
return this->inf_heap().min_value();
}
const X &get_val_for_leaving(unsigned j) const {
lp_assert(!this->column_is_feasible(j));
switch (this->m_column_types[j]) {

7
src/math/lp/lp_primal_core_solver_tableau_def.h
View file

@ -59,6 +59,7 @@ template <typename T, typename X> void lp_primal_core_solver<T, X>::advance_on_e
}
unsigned j_nz = this->m_m() + 1; // this number is greater than the max column size
std::list<unsigned>::iterator entering_iter = m_non_basis_list.end();
unsigned n = 0;
for (auto non_basis_iter = m_non_basis_list.begin(); number_of_benefitial_columns_to_go_over && non_basis_iter != m_non_basis_list.end(); ++non_basis_iter) {
unsigned j = *non_basis_iter;
if (!column_is_benefitial_for_entering_basis(j))
@ -71,8 +72,9 @@ template <typename T, typename X> void lp_primal_core_solver<T, X>::advance_on_e
entering_iter = non_basis_iter;
if (number_of_benefitial_columns_to_go_over)
number_of_benefitial_columns_to_go_over--;
n = 1;
}
else if (t == j_nz && this->m_settings.random_next() % 2 == 0) {
else if (t == j_nz && this->m_settings.random_next(++n) == 0) {
entering_iter = non_basis_iter;
}
}// while (number_of_benefitial_columns_to_go_over && initial_offset_in_non_basis != offset_in_nb);
@ -166,7 +168,8 @@ template <typename T, typename X>void lp_primal_core_solver<T, X>::advance_on_en
}
this->update_basis_and_x_tableau(entering, leaving, t);
this->iters_with_no_cost_growing() = 0;
} else {
}
else {
this->pivot_column_tableau(entering, this->m_basis_heading[leaving]);
this->change_basis(entering, leaving);
}

5
src/math/lp/lp_types.h
View file

@ -20,8 +20,9 @@ Revision History:
#pragma once
#include <sstream>
// clang-format off
#include <limits.h>
#include "util/debug.h"
namespace nla {
class core;
}

3
src/test/lp/.clang-format Normal file
View file

@ -0,0 +1,3 @@
BasedOnStyle: Google
IndentWidth: 4
ColumnLimit: 0

697
src/test/lp/lp.cpp
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