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z3/src/math/lp/permutation_matrix.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

148 lines
4.5 KiB
C++

/*++
Copyright (c) 2017 Microsoft Corporation
Module Name:
<name>
Abstract:
<abstract>
Author:
Lev Nachmanson (levnach)
Revision History:
--*/
#pragma once
#include "util/vector.h"
#include <algorithm>
#include "util/debug.h"
#include <string>
#include "math/lp/sparse_vector.h"
#include "math/lp/indexed_vector.h"
#include "math/lp/lp_settings.h"
#include "math/lp/matrix.h"
#include "math/lp/tail_matrix.h"
namespace lp {
#ifdef Z3DEBUG
inline bool is_even(int k) { return (k/2)*2 == k; }
#endif
template <typename T, typename X>
class permutation_matrix : public tail_matrix<T, X> {
vector<unsigned> m_permutation;
vector<unsigned> m_rev;
vector<unsigned> m_work_array;
vector<T> m_T_buffer;
vector<X> m_X_buffer;
class ref {
permutation_matrix & m_p;
unsigned m_i;
public:
ref(permutation_matrix & m, unsigned i):m_p(m), m_i(i) {}
ref & operator=(unsigned v) { m_p.set_val(m_i, v); return *this; }
ref & operator=(ref const & v) {
m_p.set_val(m_i, v.m_p.m_permutation[v.m_i]);
return *this;
}
operator unsigned & () const { return m_p.m_permutation[m_i]; }
};
public:
permutation_matrix() {}
permutation_matrix(unsigned length);
permutation_matrix(unsigned length, vector<unsigned> const & values);
// create a unit permutation of the given length
void init(unsigned length);
unsigned get_rev(unsigned i) { return m_rev[i]; }
bool is_dense() const override { return false; }
#ifdef Z3DEBUG
permutation_matrix get_inverse() const {
return permutation_matrix(size(), m_rev);
}
void print(std::ostream & out) const;
#endif
ref operator[](unsigned i) { return ref(*this, i); }
unsigned operator[](unsigned i) const { return m_permutation[i]; }
void apply_from_left(vector<X> & w, lp_settings &) override;
void apply_from_left_to_T(indexed_vector<T> & w, lp_settings & settings) override;
void apply_from_right(vector<T> & w) override;
void apply_from_right(indexed_vector<T> & w) override;
template <typename L>
void copy_aside(vector<L> & t, vector<unsigned> & tmp_index, indexed_vector<L> & w);
template <typename L>
void clear_data(indexed_vector<L> & w);
template <typename L>
void apply_reverse_from_left(indexed_vector<L> & w);
void apply_reverse_from_left_to_T(vector<T> & w);
void apply_reverse_from_left_to_X(vector<X> & w);
void apply_reverse_from_right_to_T(vector<T> & w);
void apply_reverse_from_right_to_T(indexed_vector<T> & w);
void apply_reverse_from_right_to_X(vector<X> & w);
void set_val(unsigned i, unsigned pi) {
lp_assert(i < size() && pi < size()); m_permutation[i] = pi; m_rev[pi] = i; }
void transpose_from_left(unsigned i, unsigned j);
unsigned apply_reverse(unsigned i) const { return m_rev[i]; }
void transpose_from_right(unsigned i, unsigned j);
#ifdef Z3DEBUG
T get_elem(unsigned i, unsigned j) const override {
return m_permutation[i] == j? numeric_traits<T>::one() : numeric_traits<T>::zero();
}
unsigned row_count() const override { return size(); }
unsigned column_count() const override { return size(); }
void set_number_of_rows(unsigned /*m*/) override { }
void set_number_of_columns(unsigned /*n*/) override { }
#endif
void multiply_by_permutation_from_left(permutation_matrix<T, X> & p);
// this is multiplication in the matrix sense
void multiply_by_permutation_from_right(permutation_matrix<T, X> & p);
void multiply_by_reverse_from_right(permutation_matrix<T, X> & q);
void multiply_by_permutation_reverse_from_left(permutation_matrix<T, X> & r);
void shrink_by_one_identity();
bool is_identity() const;
unsigned size() const { return static_cast<unsigned>(m_rev.size()); }
void resize(unsigned size) {
unsigned old_size = m_permutation.size();
m_permutation.resize(size);
m_rev.resize(size);
m_T_buffer.resize(size);
m_X_buffer.resize(size);
for (unsigned i = old_size; i < size; i++) {
m_permutation[i] = m_rev[i] = i;
}
}
}; // end of the permutation class
}