3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-04-15 13:28:47 +00:00
z3/src/math/lp/lu_def.h
Lev Nachmanson 33cbd29ed0 mv util/lp to math/lp
Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
2020-01-28 10:04:21 -08:00

991 lines
32 KiB
C++

/*++
Copyright (c) 2017 Microsoft Corporation
Module Name:
<name>
Abstract:
<abstract>
Author:
Lev Nachmanson (levnach)
Revision History:
--*/
#include <string>
#include <algorithm>
#include <set>
#include "util/vector.h"
#include <utility>
#include "util/debug.h"
#include "math/lp/lu.h"
namespace lp {
template <typename T, typename X, typename M> // print the nr x nc submatrix at the top left corner
void print_submatrix(square_sparse_matrix<T, X> & m, unsigned mr, unsigned nc, std::ostream & out) {
vector<vector<std::string>> A;
vector<unsigned> widths;
for (unsigned i = 0; i < m.row_count() && i < mr ; i++) {
A.push_back(vector<std::string>());
for (unsigned j = 0; j < m.column_count() && j < nc; j++) {
A[i].push_back(T_to_string(static_cast<T>(m(i, j))));
}
}
for (unsigned j = 0; j < m.column_count() && j < nc; j++) {
widths.push_back(get_width_of_column(j, A));
}
print_matrix_with_widths(A, widths, out);
}
template<typename M>
void print_matrix(M &m, std::ostream & out) {
vector<vector<std::string>> A;
vector<unsigned> widths;
for (unsigned i = 0; i < m.row_count(); i++) {
A.push_back(vector<std::string>());
for (unsigned j = 0; j < m.column_count(); j++) {
A[i].push_back(T_to_string(m[i][j]));
}
}
for (unsigned j = 0; j < m.column_count(); j++) {
widths.push_back(get_width_of_column(j, A));
}
print_matrix_with_widths(A, widths, out);
}
template <typename T, typename X>
one_elem_on_diag<T, X>::one_elem_on_diag(const one_elem_on_diag & o) {
m_i = o.m_i;
m_val = o.m_val;
#ifdef Z3DEBUG
m_m = m_n = o.m_m;
m_one_over_val = numeric_traits<T>::one() / o.m_val;
#endif
}
#ifdef Z3DEBUG
template <typename T, typename X>
T one_elem_on_diag<T, X>::get_elem(unsigned i, unsigned j) const {
if (i == j){
if (j == m_i) {
return m_one_over_val;
}
return numeric_traits<T>::one();
}
return numeric_traits<T>::zero();
}
#endif
template <typename T, typename X>
void one_elem_on_diag<T, X>::apply_from_left_to_T(indexed_vector<T> & w, lp_settings & settings) {
T & t = w[m_i];
if (numeric_traits<T>::is_zero(t)) {
return;
}
t /= m_val;
if (numeric_traits<T>::precise()) return;
if (settings.abs_val_is_smaller_than_drop_tolerance(t)) {
w.erase_from_index(m_i);
t = numeric_traits<T>::zero();
}
}
// This class supports updates of the columns of B, and solves systems Bx=b,and yB=c
// Using Suhl-Suhl method described in the dissertation of Achim Koberstein, Chapter 5
template <typename M>
lu<M>::lu(const M& A,
vector<unsigned>& basis,
lp_settings & settings):
m_status(LU_status::OK),
m_dim(A.row_count()),
m_A(A),
m_Q(m_dim),
m_R(m_dim),
m_r_wave(m_dim),
m_U(A, basis), // create the square matrix that eventually will be factorized
m_settings(settings),
m_failure(false),
m_row_eta_work_vector(A.row_count()),
m_refactor_counter(0) {
lp_assert(!(numeric_traits<T>::precise() && settings.use_tableau()));
#ifdef Z3DEBUG
debug_test_of_basis(A, basis);
#endif
++m_settings.st().m_num_factorizations;
create_initial_factorization();
#ifdef Z3DEBUG
// lp_assert(check_correctness());
#endif
}
template <typename M>
lu<M>::lu(const M& A,
lp_settings & settings):
m_status(LU_status::OK),
m_dim(A.row_count()),
m_A(A),
m_Q(m_dim),
m_R(m_dim),
m_r_wave(m_dim),
m_U(A), // create the square matrix that eventually will be factorized
m_settings(settings),
m_failure(false),
m_row_eta_work_vector(A.row_count()),
m_refactor_counter(0) {
lp_assert(A.row_count() == A.column_count());
create_initial_factorization();
#ifdef Z3DEBUG
lp_assert(is_correct());
#endif
}
template <typename M>
void lu<M>::debug_test_of_basis( M const & A, vector<unsigned> & basis) {
std::set<unsigned> set;
for (unsigned i = 0; i < A.row_count(); i++) {
lp_assert(basis[i]< A.column_count());
set.insert(basis[i]);
}
lp_assert(set.size() == A.row_count());
}
template <typename M>
void lu<M>::solve_By(indexed_vector<X> & y) {
lp_assert(false); // not implemented
// init_vector_y(y);
// solve_By_when_y_is_ready(y);
}
template <typename M>
void lu<M>::solve_By(vector<X> & y) {
init_vector_y(y);
solve_By_when_y_is_ready_for_X(y);
}
template <typename M>
void lu<M>::solve_By_when_y_is_ready_for_X(vector<X> & y) {
if (numeric_traits<T>::precise()) {
m_U.solve_U_y(y);
m_R.apply_reverse_from_left_to_X(y); // see 24.3 from Chvatal
return;
}
m_U.double_solve_U_y(y);
m_R.apply_reverse_from_left_to_X(y); // see 24.3 from Chvatal
unsigned i = m_dim;
while (i--) {
if (is_zero(y[i])) continue;
if (m_settings.abs_val_is_smaller_than_drop_tolerance(y[i])){
y[i] = zero_of_type<X>();
}
}
}
template <typename M>
void lu<M>::solve_By_when_y_is_ready_for_T(vector<T> & y, vector<unsigned> & index) {
if (numeric_traits<T>::precise()) {
m_U.solve_U_y(y);
m_R.apply_reverse_from_left_to_T(y); // see 24.3 from Chvatal
unsigned j = m_dim;
while (j--) {
if (!is_zero(y[j]))
index.push_back(j);
}
return;
}
m_U.double_solve_U_y(y);
m_R.apply_reverse_from_left_to_T(y); // see 24.3 from Chvatal
unsigned i = m_dim;
while (i--) {
if (is_zero(y[i])) continue;
if (m_settings.abs_val_is_smaller_than_drop_tolerance(y[i])){
y[i] = zero_of_type<T>();
} else {
index.push_back(i);
}
}
}
template <typename M>
void lu<M>::solve_By_for_T_indexed_only(indexed_vector<T> & y, const lp_settings & settings) {
if (numeric_traits<T>::precise()) {
vector<unsigned> active_rows;
m_U.solve_U_y_indexed_only(y, settings, active_rows);
m_R.apply_reverse_from_left(y); // see 24.3 from Chvatal
return;
}
m_U.double_solve_U_y(y, m_settings);
m_R.apply_reverse_from_left(y); // see 24.3 from Chvatal
}
template <typename M>
void lu<M>::print_matrix_compact(std::ostream & f) {
f << "matrix_start" << std::endl;
f << "nrows " << m_A.row_count() << std::endl;
f << "ncolumns " << m_A.column_count() << std::endl;
for (unsigned i = 0; i < m_A.row_count(); i++) {
auto & row = m_A.m_rows[i];
f << "row " << i << std::endl;
for (auto & t : row) {
f << "column " << t.m_j << " value " << t.m_value << std::endl;
}
f << "row_end" << std::endl;
}
f << "matrix_end" << std::endl;
}
template <typename M>
void lu< M>::print(indexed_vector<T> & w, const vector<unsigned>& basis) {
std::string dump_file_name("/tmp/lu");
remove(dump_file_name.c_str());
std::ofstream f(dump_file_name);
if (!f.is_open()) {
LP_OUT(m_settings, "cannot open file " << dump_file_name << std::endl);
return;
}
LP_OUT(m_settings, "writing lu dump to " << dump_file_name << std::endl);
print_matrix_compact(f);
print_vector(basis, f);
print_indexed_vector(w, f);
f.close();
}
template <typename M>
void lu< M>::solve_Bd(unsigned a_column, indexed_vector<T> & d, indexed_vector<T> & w) {
init_vector_w(a_column, w);
if (w.m_index.size() * ratio_of_index_size_to_all_size<T>() < d.m_data.size()) { // this const might need some tuning
d = w;
solve_By_for_T_indexed_only(d, m_settings);
} else {
d.m_data = w.m_data;
d.m_index.clear();
solve_By_when_y_is_ready_for_T(d.m_data, d.m_index);
}
}
template <typename M>
void lu< M>::solve_Bd_faster(unsigned a_column, indexed_vector<T> & d) { // puts the a_column into d
init_vector_w(a_column, d);
solve_By_for_T_indexed_only(d, m_settings);
}
template <typename M>
void lu< M>::solve_yB(vector<T>& y) {
// first solve yU = cb*R(-1)
m_R.apply_reverse_from_right_to_T(y); // got y = cb*R(-1)
m_U.solve_y_U(y); // got y*U=cb*R(-1)
m_Q.apply_reverse_from_right_to_T(y); //
for (auto e = m_tail.rbegin(); e != m_tail.rend(); ++e) {
#ifdef Z3DEBUG
(*e)->set_number_of_columns(m_dim);
#endif
(*e)->apply_from_right(y);
}
}
template <typename M>
void lu< M>::solve_yB_indexed(indexed_vector<T>& y) {
lp_assert(y.is_OK());
// first solve yU = cb*R(-1)
m_R.apply_reverse_from_right_to_T(y); // got y = cb*R(-1)
lp_assert(y.is_OK());
m_U.solve_y_U_indexed(y, m_settings); // got y*U=cb*R(-1)
lp_assert(y.is_OK());
m_Q.apply_reverse_from_right_to_T(y);
lp_assert(y.is_OK());
for (auto e = m_tail.rbegin(); e != m_tail.rend(); ++e) {
#ifdef Z3DEBUG
(*e)->set_number_of_columns(m_dim);
#endif
(*e)->apply_from_right(y);
lp_assert(y.is_OK());
}
}
template <typename M>
void lu< M>::add_delta_to_solution(const vector<T>& yc, vector<T>& y){
unsigned i = static_cast<unsigned>(y.size());
while (i--)
y[i]+=yc[i];
}
template <typename M>
void lu< M>::add_delta_to_solution_indexed(indexed_vector<T>& y) {
// the delta sits in m_y_copy, put result into y
lp_assert(y.is_OK());
lp_assert(m_y_copy.is_OK());
m_ii.clear();
m_ii.resize(y.data_size());
for (unsigned i : y.m_index)
m_ii.set_value(1, i);
for (unsigned i : m_y_copy.m_index) {
y.m_data[i] += m_y_copy[i];
if (m_ii[i] == 0)
m_ii.set_value(1, i);
}
lp_assert(m_ii.is_OK());
y.m_index.clear();
for (unsigned i : m_ii.m_index) {
T & v = y.m_data[i];
if (!lp_settings::is_eps_small_general(v, 1e-14))
y.m_index.push_back(i);
else if (!numeric_traits<T>::is_zero(v))
v = zero_of_type<T>();
}
lp_assert(y.is_OK());
}
template <typename M>
void lu< M>::find_error_of_yB(vector<T>& yc, const vector<T>& y, const vector<unsigned>& m_basis) {
unsigned i = m_dim;
while (i--) {
yc[i] -= m_A.dot_product_with_column(y, m_basis[i]);
}
}
template <typename M>
void lu< M>::find_error_of_yB_indexed(const indexed_vector<T>& y, const vector<int>& heading, const lp_settings& settings) {
#if 0 == 1
// it is a non efficient version
indexed_vector<T> yc = m_y_copy;
yc.m_index.clear();
lp_assert(!numeric_traits<T>::precise());
{
vector<unsigned> d_basis(y.m_data.size());
for (unsigned j = 0; j < heading.size(); j++) {
if (heading[j] >= 0) {
d_basis[heading[j]] = j;
}
}
unsigned i = m_dim;
while (i--) {
T & v = yc.m_data[i] -= m_A.dot_product_with_column(y.m_data, d_basis[i]);
if (settings.abs_val_is_smaller_than_drop_tolerance(v))
v = zero_of_type<T>();
else
yc.m_index.push_back(i);
}
}
#endif
lp_assert(m_ii.is_OK());
m_ii.clear();
m_ii.resize(y.data_size());
lp_assert(m_y_copy.is_OK());
// put the error into m_y_copy
for (auto k : y.m_index) {
auto & row = m_A.m_rows[k];
const T & y_k = y.m_data[k];
for (auto & c : row) {
unsigned j = c.var();
int hj = heading[j];
if (hj < 0) continue;
if (m_ii.m_data[hj] == 0)
m_ii.set_value(1, hj);
m_y_copy.m_data[hj] -= c.get_val() * y_k;
}
}
// add the index of m_y_copy to m_ii
for (unsigned i : m_y_copy.m_index) {
if (m_ii.m_data[i] == 0)
m_ii.set_value(1, i);
}
// there is no guarantee that m_y_copy is OK here, but its index
// is contained in m_ii index
m_y_copy.m_index.clear();
// setup the index of m_y_copy
for (auto k : m_ii.m_index) {
T& v = m_y_copy.m_data[k];
if (settings.abs_val_is_smaller_than_drop_tolerance(v))
v = zero_of_type<T>();
else {
m_y_copy.set_value(v, k);
}
}
lp_assert(m_y_copy.is_OK());
}
// solves y*B = y
// y is the input
template <typename M>
void lu< M>::solve_yB_with_error_check_indexed(indexed_vector<T> & y, const vector<int>& heading, const vector<unsigned> & basis, const lp_settings & settings) {
if (numeric_traits<T>::precise()) {
if (y.m_index.size() * ratio_of_index_size_to_all_size<T>() * 3 < m_A.column_count()) {
solve_yB_indexed(y);
} else {
solve_yB(y.m_data);
y.restore_index_and_clean_from_data();
}
return;
}
lp_assert(m_y_copy.is_OK());
lp_assert(y.is_OK());
if (y.m_index.size() * ratio_of_index_size_to_all_size<T>() < m_A.column_count()) {
m_y_copy = y;
solve_yB_indexed(y);
lp_assert(y.is_OK());
if (y.m_index.size() * ratio_of_index_size_to_all_size<T>() >= m_A.column_count()) {
find_error_of_yB(m_y_copy.m_data, y.m_data, basis);
solve_yB(m_y_copy.m_data);
add_delta_to_solution(m_y_copy.m_data, y.m_data);
y.restore_index_and_clean_from_data();
m_y_copy.clear_all();
} else {
find_error_of_yB_indexed(y, heading, settings); // this works with m_y_copy
solve_yB_indexed(m_y_copy);
add_delta_to_solution_indexed(y);
}
lp_assert(m_y_copy.is_OK());
} else {
solve_yB_with_error_check(y.m_data, basis);
y.restore_index_and_clean_from_data();
}
}
// solves y*B = y
// y is the input
template <typename M>
void lu< M>::solve_yB_with_error_check(vector<T> & y, const vector<unsigned>& basis) {
if (numeric_traits<T>::precise()) {
solve_yB(y);
return;
}
auto & yc = m_y_copy.m_data;
yc =y; // copy y aside
solve_yB(y);
find_error_of_yB(yc, y, basis);
solve_yB(yc);
add_delta_to_solution(yc, y);
m_y_copy.clear_all();
}
template <typename M>
void lu< M>::apply_Q_R_to_U(permutation_matrix<T, X> & r_wave) {
m_U.multiply_from_right(r_wave);
m_U.multiply_from_left_with_reverse(r_wave);
}
// Solving yB = cb to find the entering variable,
// where cb is the cost vector projected to B.
// The result is stored in cb.
// solving Bd = a ( to find the column d of B^{-1} A_N corresponding to the entering
// variable
template <typename M>
lu< M>::~lu(){
for (auto t : m_tail) {
delete t;
}
}
template <typename M>
void lu< M>::init_vector_y(vector<X> & y) {
apply_lp_list_to_y(y);
m_Q.apply_reverse_from_left_to_X(y);
}
template <typename M>
void lu< M>::perform_transformations_on_w(indexed_vector<T>& w) {
apply_lp_list_to_w(w);
m_Q.apply_reverse_from_left(w);
// TBD does not compile: lp_assert(numeric_traits<T>::precise() || check_vector_for_small_values(w, m_settings));
}
// see Chvatal 24.3
template <typename M>
void lu< M>::init_vector_w(unsigned entering, indexed_vector<T> & w) {
w.clear();
m_A.copy_column_to_indexed_vector(entering, w); // w = a, the column
perform_transformations_on_w(w);
}
template <typename M>
void lu< M>::apply_lp_list_to_w(indexed_vector<T> & w) {
for (unsigned i = 0; i < m_tail.size(); i++) {
m_tail[i]->apply_from_left_to_T(w, m_settings);
// TBD does not compile: lp_assert(check_vector_for_small_values(w, m_settings));
}
}
template <typename M>
void lu< M>::apply_lp_list_to_y(vector<X>& y) {
for (unsigned i = 0; i < m_tail.size(); i++) {
m_tail[i]->apply_from_left(y, m_settings);
}
}
template <typename M>
void lu< M>::swap_rows(int j, int k) {
if (j != k) {
m_Q.transpose_from_left(j, k);
m_U.swap_rows(j, k);
}
}
template <typename M>
void lu< M>::swap_columns(int j, int pivot_column) {
if (j == pivot_column)
return;
m_R.transpose_from_right(j, pivot_column);
m_U.swap_columns(j, pivot_column);
}
template <typename M>
bool lu< M>::pivot_the_row(int row) {
eta_matrix<T, X> * eta_matrix = get_eta_matrix_for_pivot(row);
if (get_status() != LU_status::OK) {
return false;
}
if (eta_matrix == nullptr) {
m_U.shorten_active_matrix(row, nullptr);
return true;
}
if (!m_U.pivot_with_eta(row, eta_matrix, m_settings))
return false;
eta_matrix->conjugate_by_permutation(m_Q);
push_matrix_to_tail(eta_matrix);
return true;
}
// we're processing the column j now
template <typename M>
eta_matrix<typename M::coefftype, typename M::argtype> * lu< M>::get_eta_matrix_for_pivot(unsigned j) {
eta_matrix<T, X> *ret;
if(!m_U.fill_eta_matrix(j, &ret)) {
set_status(LU_status::Degenerated);
}
return ret;
}
// we're processing the column j now
template <typename M>
eta_matrix<typename M::coefftype, typename M::argtype> * lu<M>::get_eta_matrix_for_pivot(unsigned j, square_sparse_matrix<T, X>& copy_of_U) {
eta_matrix<T, X> *ret;
copy_of_U.fill_eta_matrix(j, &ret);
return ret;
}
// see page 407 of Chvatal
template <typename M>
unsigned lu<M>::transform_U_to_V_by_replacing_column(indexed_vector<T> & w,
unsigned leaving_column) {
unsigned column_to_replace = m_R.apply_reverse(leaving_column);
m_U.replace_column(column_to_replace, w, m_settings);
return column_to_replace;
}
#ifdef Z3DEBUG
template <typename M>
void lu<M>::check_vector_w(unsigned entering) {
T * w = new T[m_dim];
m_A.copy_column_to_vector(entering, w);
check_apply_lp_lists_to_w(w);
delete [] w;
}
template <typename M>
void lu<M>::check_apply_matrix_to_vector(matrix<T, X> *lp, T *w) {
if (lp != nullptr) {
lp -> set_number_of_rows(m_dim);
lp -> set_number_of_columns(m_dim);
apply_to_vector(*lp, w);
}
}
template <typename M>
void lu<M>::check_apply_lp_lists_to_w(T * w) {
for (unsigned i = 0; i < m_tail.size(); i++) {
check_apply_matrix_to_vector(m_tail[i], w);
}
permutation_matrix<T, X> qr = m_Q.get_reverse();
apply_to_vector(qr, w);
for (int i = m_dim - 1; i >= 0; i--) {
lp_assert(abs(w[i] - w[i]) < 0.0000001);
}
}
#endif
template <typename M>
void lu<M>::process_column(int j) {
unsigned pi, pj;
bool success = m_U.get_pivot_for_column(pi, pj, m_settings.c_partial_pivoting, j);
if (!success) {
// LP_OUT(m_settings, "get_pivot returned false: cannot find the pivot for column " << j << std::endl);
m_failure = true;
return;
}
if (static_cast<int>(pi) == -1) {
// LP_OUT(m_settings, "cannot find the pivot for column " << j << std::endl);
m_failure = true;
return;
}
swap_columns(j, pj);
swap_rows(j, pi);
if (!pivot_the_row(j)) {
// LP_OUT(m_settings, "pivot_the_row(" << j << ") failed" << std::endl);
m_failure = true;
}
}
template <typename M>
bool lu<M>::is_correct(const vector<unsigned>& basis) {
#ifdef Z3DEBUG
if (get_status() != LU_status::OK) {
return false;
}
dense_matrix<T, X> left_side = get_left_side(basis);
dense_matrix<T, X> right_side = get_right_side();
return left_side == right_side;
#else
return true;
#endif
}
template <typename M>
bool lu<M>::is_correct() {
#ifdef Z3DEBUG
if (get_status() != LU_status::OK) {
return false;
}
dense_matrix<T, X> left_side = get_left_side();
dense_matrix<T, X> right_side = get_right_side();
return left_side == right_side;
#else
return true;
#endif
}
#ifdef Z3DEBUG
template <typename M>
dense_matrix<typename M::coefftype, typename M::argtype> lu<M>::tail_product() {
lp_assert(tail_size() > 0);
dense_matrix<T, X> left_side = permutation_matrix<T, X>(m_dim);
for (unsigned i = 0; i < tail_size(); i++) {
matrix<T, X>* lp = get_lp_matrix(i);
lp->set_number_of_rows(m_dim);
lp->set_number_of_columns(m_dim);
left_side = ((*lp) * left_side);
}
return left_side;
}
template <typename M>
dense_matrix<typename M::coefftype, typename M::argtype> lu<M>::get_left_side(const vector<unsigned>& basis) {
dense_matrix<T, X> left_side = get_B(*this, basis);
for (unsigned i = 0; i < tail_size(); i++) {
matrix<T, X>* lp = get_lp_matrix(i);
lp->set_number_of_rows(m_dim);
lp->set_number_of_columns(m_dim);
left_side = ((*lp) * left_side);
}
return left_side;
}
template <typename M>
dense_matrix<typename M::coefftype, typename M::argtype> lu<M>::get_left_side() {
dense_matrix<T, X> left_side = get_B(*this);
for (unsigned i = 0; i < tail_size(); i++) {
matrix<T, X>* lp = get_lp_matrix(i);
lp->set_number_of_rows(m_dim);
lp->set_number_of_columns(m_dim);
left_side = ((*lp) * left_side);
}
return left_side;
}
template <typename M>
dense_matrix<typename M::coefftype, typename M::argtype> lu<M>::get_right_side() {
auto ret = U() * R();
ret = Q() * ret;
return ret;
}
#endif
// needed for debugging purposes
template <typename M>
void lu<M>::copy_w(T *buffer, indexed_vector<T> & w) {
unsigned i = m_dim;
while (i--) {
buffer[i] = w[i];
}
}
// needed for debugging purposes
template <typename M>
void lu<M>::restore_w(T *buffer, indexed_vector<T> & w) {
unsigned i = m_dim;
while (i--) {
w[i] = buffer[i];
}
}
template <typename M>
bool lu<M>::all_columns_and_rows_are_active() {
unsigned i = m_dim;
while (i--) {
lp_assert(m_U.col_is_active(i));
lp_assert(m_U.row_is_active(i));
}
return true;
}
template <typename M>
bool lu<M>::too_dense(unsigned j) const {
unsigned r = m_dim - j;
if (r < 5)
return false;
// if (j * 5 < m_dim * 4) // start looking for dense only at the bottom of the rows
// return false;
// return r * r * m_settings.density_threshold <= m_U.get_number_of_nonzeroes_below_row(j);
return r * r * m_settings.density_threshold <= m_U.get_n_of_active_elems();
}
template <typename M>
void lu<M>::pivot_in_dense_mode(unsigned i) {
int j = m_dense_LU->find_pivot_column_in_row(i);
if (j == -1) {
m_failure = true;
return;
}
if (i != static_cast<unsigned>(j)) {
swap_columns(i, j);
m_dense_LU->swap_columns(i, j);
}
m_dense_LU->pivot(i, m_settings);
}
template <typename M>
void lu<M>::create_initial_factorization(){
m_U.prepare_for_factorization();
unsigned j;
for (j = 0; j < m_dim; j++) {
process_column(j);
if (m_failure) {
set_status(LU_status::Degenerated);
return;
}
if (too_dense(j)) {
break;
}
}
if (j == m_dim) {
// TBD does not compile: lp_assert(m_U.is_upper_triangular_and_maximums_are_set_correctly_in_rows(m_settings));
// lp_assert(is_correct());
// lp_assert(m_U.is_upper_triangular_and_maximums_are_set_correctly_in_rows(m_settings));
return;
}
j++;
m_dense_LU = new square_dense_submatrix<T, X>(&m_U, j);
for (; j < m_dim; j++) {
pivot_in_dense_mode(j);
if (m_failure) {
set_status(LU_status::Degenerated);
return;
}
}
m_dense_LU->update_parent_matrix(m_settings);
lp_assert(m_dense_LU->is_L_matrix());
m_dense_LU->conjugate_by_permutation(m_Q);
push_matrix_to_tail(m_dense_LU);
m_refactor_counter = 0;
// lp_assert(is_correct());
// lp_assert(m_U.is_upper_triangular_and_maximums_are_set_correctly_in_rows(m_settings));
}
template <typename M>
void lu<M>::calculate_r_wave_and_update_U(unsigned bump_start, unsigned bump_end, permutation_matrix<T, X> & r_wave) {
if (bump_start > bump_end) {
set_status(LU_status::Degenerated);
return;
}
if (bump_start == bump_end) {
return;
}
r_wave[bump_start] = bump_end; // sending the offensive column to the end of the bump
for ( unsigned i = bump_start + 1 ; i <= bump_end; i++ ) {
r_wave[i] = i - 1;
}
m_U.multiply_from_right(r_wave);
m_U.multiply_from_left_with_reverse(r_wave);
}
template <typename M>
void lu<M>::scan_last_row_to_work_vector(unsigned lowest_row_of_the_bump) {
vector<indexed_value<T>> & last_row_vec = m_U.get_row_values(m_U.adjust_row(lowest_row_of_the_bump));
for (auto & iv : last_row_vec) {
if (is_zero(iv.m_value)) continue;
lp_assert(!m_settings.abs_val_is_smaller_than_drop_tolerance(iv.m_value));
unsigned adjusted_col = m_U.adjust_column_inverse(iv.m_index);
if (adjusted_col < lowest_row_of_the_bump) {
m_row_eta_work_vector.set_value(-iv.m_value, adjusted_col);
} else {
m_row_eta_work_vector.set_value(iv.m_value, adjusted_col); // preparing to calculate the real value in the matrix
}
}
}
template <typename M>
void lu<M>::pivot_and_solve_the_system(unsigned replaced_column, unsigned lowest_row_of_the_bump) {
// we have the system right side at m_row_eta_work_vector now
// solve the system column wise
for (unsigned j = replaced_column; j < lowest_row_of_the_bump; j++) {
T v = m_row_eta_work_vector[j];
if (numeric_traits<T>::is_zero(v)) continue; // this column does not contribute to the solution
unsigned aj = m_U.adjust_row(j);
vector<indexed_value<T>> & row = m_U.get_row_values(aj);
for (auto & iv : row) {
unsigned col = m_U.adjust_column_inverse(iv.m_index);
lp_assert(col >= j || numeric_traits<T>::is_zero(iv.m_value));
if (col == j) continue;
if (numeric_traits<T>::is_zero(iv.m_value)) {
continue;
}
// the -v is for solving the system ( to zero the last row), and +v is for pivoting
T delta = col < lowest_row_of_the_bump? -v * iv.m_value: v * iv.m_value;
lp_assert(numeric_traits<T>::is_zero(delta) == false);
// m_row_eta_work_vector.add_value_at_index_with_drop_tolerance(col, delta);
if (numeric_traits<T>::is_zero(m_row_eta_work_vector[col])) {
if (!m_settings.abs_val_is_smaller_than_drop_tolerance(delta)){
m_row_eta_work_vector.set_value(delta, col);
}
} else {
T t = (m_row_eta_work_vector[col] += delta);
if (m_settings.abs_val_is_smaller_than_drop_tolerance(t)){
m_row_eta_work_vector[col] = numeric_traits<T>::zero();
auto it = std::find(m_row_eta_work_vector.m_index.begin(), m_row_eta_work_vector.m_index.end(), col);
if (it != m_row_eta_work_vector.m_index.end())
m_row_eta_work_vector.m_index.erase(it);
}
}
}
}
}
// see Achim Koberstein's thesis page 58, but here we solve the system and pivot to the last
// row at the same time
template <typename M>
row_eta_matrix<typename M::coefftype, typename M::argtype> *lu<M>::get_row_eta_matrix_and_set_row_vector(unsigned replaced_column, unsigned lowest_row_of_the_bump, const T & pivot_elem_for_checking) {
if (replaced_column == lowest_row_of_the_bump) return nullptr;
scan_last_row_to_work_vector(lowest_row_of_the_bump);
pivot_and_solve_the_system(replaced_column, lowest_row_of_the_bump);
if (numeric_traits<T>::precise() == false && !is_zero(pivot_elem_for_checking)) {
T denom = std::max(T(1), abs(pivot_elem_for_checking));
if (
!m_settings.abs_val_is_smaller_than_pivot_tolerance((m_row_eta_work_vector[lowest_row_of_the_bump] - pivot_elem_for_checking) / denom)) {
set_status(LU_status::Degenerated);
// LP_OUT(m_settings, "diagonal element is off" << std::endl);
return nullptr;
}
}
#ifdef Z3DEBUG
auto ret = new row_eta_matrix<typename M::coefftype, typename M::argtype>(replaced_column, lowest_row_of_the_bump, m_dim);
#else
auto ret = new row_eta_matrix<typename M::coefftype, typename M::argtype>(replaced_column, lowest_row_of_the_bump);
#endif
for (auto j : m_row_eta_work_vector.m_index) {
if (j < lowest_row_of_the_bump) {
auto & v = m_row_eta_work_vector[j];
if (!is_zero(v)) {
if (!m_settings.abs_val_is_smaller_than_drop_tolerance(v)){
ret->push_back(j, v);
}
v = numeric_traits<T>::zero();
}
}
} // now the lowest_row_of_the_bump contains the rest of the row to the right of the bump with correct values
return ret;
}
template <typename M>
void lu<M>::replace_column(T pivot_elem_for_checking, indexed_vector<T> & w, unsigned leaving_column_of_U){
m_refactor_counter++;
unsigned replaced_column = transform_U_to_V_by_replacing_column( w, leaving_column_of_U);
unsigned lowest_row_of_the_bump = m_U.lowest_row_in_column(replaced_column);
m_r_wave.init(m_dim);
calculate_r_wave_and_update_U(replaced_column, lowest_row_of_the_bump, m_r_wave);
auto row_eta = get_row_eta_matrix_and_set_row_vector(replaced_column, lowest_row_of_the_bump, pivot_elem_for_checking);
if (get_status() == LU_status::Degenerated) {
m_row_eta_work_vector.clear_all();
return;
}
m_Q.multiply_by_permutation_from_right(m_r_wave);
m_R.multiply_by_permutation_reverse_from_left(m_r_wave);
if (row_eta != nullptr) {
row_eta->conjugate_by_permutation(m_Q);
push_matrix_to_tail(row_eta);
}
calculate_Lwave_Pwave_for_bump(replaced_column, lowest_row_of_the_bump);
// lp_assert(m_U.is_upper_triangular_and_maximums_are_set_correctly_in_rows(m_settings));
// lp_assert(w.is_OK() && m_row_eta_work_vector.is_OK());
}
template <typename M>
void lu<M>::calculate_Lwave_Pwave_for_bump(unsigned replaced_column, unsigned lowest_row_of_the_bump){
T diagonal_elem;
if (replaced_column < lowest_row_of_the_bump) {
diagonal_elem = m_row_eta_work_vector[lowest_row_of_the_bump];
// lp_assert(m_row_eta_work_vector.is_OK());
m_U.set_row_from_work_vector_and_clean_work_vector_not_adjusted(m_U.adjust_row(lowest_row_of_the_bump), m_row_eta_work_vector, m_settings);
} else {
diagonal_elem = m_U(lowest_row_of_the_bump, lowest_row_of_the_bump); // todo - get it more efficiently
}
if (m_settings.abs_val_is_smaller_than_pivot_tolerance(diagonal_elem)) {
set_status(LU_status::Degenerated);
return;
}
calculate_Lwave_Pwave_for_last_row(lowest_row_of_the_bump, diagonal_elem);
// lp_assert(m_U.is_upper_triangular_and_maximums_are_set_correctly_in_rows(m_settings));
}
template <typename M>
void lu<M>::calculate_Lwave_Pwave_for_last_row(unsigned lowest_row_of_the_bump, T diagonal_element) {
auto l = new one_elem_on_diag<T, X>(lowest_row_of_the_bump, diagonal_element);
#ifdef Z3DEBUG
l->set_number_of_columns(m_dim);
#endif
push_matrix_to_tail(l);
m_U.divide_row_by_constant(lowest_row_of_the_bump, diagonal_element, m_settings);
l->conjugate_by_permutation(m_Q);
}
template <typename M>
void init_factorization(lu<M>* & factorization, M & m_A, vector<unsigned> & m_basis, lp_settings &m_settings) {
if (factorization != nullptr)
delete factorization;
factorization = new lu<M>(m_A, m_basis, m_settings);
// if (factorization->get_status() != LU_status::OK)
// LP_OUT(m_settings, "failing in init_factorization" << std::endl);
}
#ifdef Z3DEBUG
template <typename M>
dense_matrix<typename M::coefftype, typename M::argtype> get_B(lu<M>& f, const vector<unsigned>& basis) {
lp_assert(basis.size() == f.dimension());
lp_assert(basis.size() == f.m_U.dimension());
dense_matrix<typename M::coefftype, typename M::argtype> B(f.dimension(), f.dimension());
for (unsigned i = 0; i < f.dimension(); i++)
for (unsigned j = 0; j < f.dimension(); j++)
B.set_elem(i, j, f.B_(i, j, basis));
return B;
}
template <typename M>
dense_matrix<typename M::coefftype, typename M::argtype> get_B(lu<M>& f) {
dense_matrix<typename M::coefftype, typename M::argtype> B(f.dimension(), f.dimension());
for (unsigned i = 0; i < f.dimension(); i++)
for (unsigned j = 0; j < f.dimension(); j++)
B.set_elem(i, j, f.m_A[i][j]);
return B;
}
#endif
}