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z3/src/math/lp/scaler.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

94 lines
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C++

/*++
Copyright (c) 2017 Microsoft Corporation
Module Name:
<name>
Abstract:
<abstract>
Author:
Lev Nachmanson (levnach)
Revision History:
--*/
#pragma once
#include "util/vector.h"
#include <math.h>
#include <algorithm>
#include <stdio.h> /* printf, fopen */
#include <stdlib.h> /* exit, EXIT_FAILURE */
#include "math/lp/lp_utils.h"
#include "math/lp/static_matrix.h"
namespace lp {
// for scaling an LP
template <typename T, typename X>
class scaler {
vector<X> & m_b; // right side
static_matrix<T, X> &m_A; // the constraint matrix
const T & m_scaling_minimum;
const T & m_scaling_maximum;
vector<T>& m_column_scale;
lp_settings & m_settings;
public:
// constructor
scaler(vector<X> & b, static_matrix<T, X> &A, const T & scaling_minimum, const T & scaling_maximum, vector<T> & column_scale,
lp_settings & settings):
m_b(b),
m_A(A),
m_scaling_minimum(scaling_minimum),
m_scaling_maximum(scaling_maximum),
m_column_scale(column_scale),
m_settings(settings) {
lp_assert(m_column_scale.size() == 0);
m_column_scale.resize(m_A.column_count(), numeric_traits<T>::one());
}
T right_side_balance();
T get_balance() { return m_A.get_balance(); }
T A_min() const;
T A_max() const;
T get_A_ratio() const;
T get_max_ratio_on_rows() const;
T get_max_ratio_on_columns() const;
void scale_rows_with_geometric_mean();
void scale_columns_with_geometric_mean();
void scale_once_for_ratio();
bool scale_with_ratio();
void bring_row_maximums_to_one();
void bring_column_maximums_to_one();
void bring_rows_and_columns_maximums_to_one();
bool scale_with_log_balance();
// Returns true if and only if the scaling was successful.
// It is the caller responsibility to restore the matrix
bool scale();
void scale_rows();
void scale_row(unsigned i);
void scale_column(unsigned i);
void scale_columns();
};
}