operations_research::sat::LinearConstraint Struct Reference

Detailed Description

One linear constraint on a set of Integer variables. Important: there should be no duplicate variables.

We also assume that we never have integer overflow when evaluating such constraint at the ROOT node. This should be enforced by the checker for user given constraints, and we must enforce it ourselves for the newly created constraint. See ValidateLinearConstraintForOverflow().

Definition at line 48 of file linear_constraint.h.

#include <linear_constraint.h>

Public Member Functions
	LinearConstraint ()=default
	LinearConstraint (IntegerValue _lb, IntegerValue _ub)
double	NormalizedViolation (const util_intops::StrongVector< IntegerVariable, double > &lp_values) const
void	resize (int size)
std::string	DebugString () const
bool	IsEqualIgnoringBounds (const LinearConstraint &other) const
bool	operator== (const LinearConstraint &other) const
absl::Span< const IntegerVariable >	VarsAsSpan () const
absl::Span< const IntegerValue >	CoeffsAsSpan () const

Public Attributes
IntegerValue	lb
IntegerValue	ub
int	num_terms = 0
std::unique_ptr< IntegerVariable[]>	vars
std::unique_ptr< IntegerValue[]>	coeffs

Constructor & Destructor Documentation

LinearConstraint() [1/2]

operations_research::sat::LinearConstraint::LinearConstraint ( )

default

LinearConstraint() [2/2]

operations_research::sat::LinearConstraint::LinearConstraint ( IntegerValue _lb, IntegerValue _ub )

inline

Definition at line 67 of file linear_constraint.h.

Member Function Documentation

CoeffsAsSpan()

absl::Span< const IntegerValue > operations_research::sat::LinearConstraint::CoeffsAsSpan ( ) const

inline

Definition at line 130 of file linear_constraint.h.

DebugString()

std::string operations_research::sat::LinearConstraint::DebugString ( ) const

inline

Definition at line 91 of file linear_constraint.h.

IsEqualIgnoringBounds()

bool operations_research::sat::LinearConstraint::IsEqualIgnoringBounds ( const LinearConstraint & other ) const

inline

Definition at line 106 of file linear_constraint.h.

NormalizedViolation()

double operations_research::sat::LinearConstraint::NormalizedViolation

(

const util_intops::StrongVector< IntegerVariable, double > &

lp_values

)

const

Compute the normalized violation of the constraint. For a cut, this is the usual definition of its efficacy.

Definition at line 174 of file linear_constraint.cc.

operator==()

bool operations_research::sat::LinearConstraint::operator== ( const LinearConstraint & other ) const

inline

Definition at line 120 of file linear_constraint.h.

resize()

void operations_research::sat::LinearConstraint::resize ( int size )

inline

Resize the LinearConstraint to have space for num_terms. We always re-allocate if the size is different to always be tight in memory.

Definition at line 77 of file linear_constraint.h.

VarsAsSpan()

absl::Span< const IntegerVariable > operations_research::sat::LinearConstraint::VarsAsSpan ( ) const

inline

Definition at line 126 of file linear_constraint.h.

Member Data Documentation

coeffs

std::unique_ptr<IntegerValue[]> operations_research::sat::LinearConstraint::coeffs

Definition at line 64 of file linear_constraint.h.

lb

IntegerValue operations_research::sat::LinearConstraint::lb

Definition at line 49 of file linear_constraint.h.

num_terms

int operations_research::sat::LinearConstraint::num_terms = 0

Rather than using two std::vector<> this class is optimized for memory consumption, given that most of our LinearConstraint are constructed once and for all.

It is however up to clients to maintain the invariants that both vars and coeffs are properly allocated and of size num_terms.

Also note that we did not add a copy constructor, to make sure that this is moved as often as possible. This allowed to optimize a few call site and so far we never copy this.

Definition at line 62 of file linear_constraint.h.

ub

IntegerValue operations_research::sat::LinearConstraint::ub

Definition at line 50 of file linear_constraint.h.

vars

std::unique_ptr<IntegerVariable[]> operations_research::sat::LinearConstraint::vars

Definition at line 63 of file linear_constraint.h.

---

The documentation for this struct was generated from the following files:

• ortools/sat/linear_constraint.h
• ortools/sat/linear_constraint.cc