LSModel Class¶

Summary¶

Functions¶

createConstant	Creates a constant expression representing the given value.
createExpression	Creates an expression of the given type, with the given ordered operands.
createNativeFunction	Creates a native function.
createFunction	Creates a function.
boolVar	Creates a boolean decision.
floatVar	Creates a float decision.
intVar	Creates an integer decision.
sum	Creates a sum expression.
sub	Creates a substraction expression.
call	Creates a call expression.
prod	Creates a product expression.
max	Creates a maximum expression.
min	Creates a minimum expression.
or_	Creates a OR expression.
and_	Creates an AND expression.
xor_	Creates a XOR expression.
not_	Creates a NOT expression.
eq	Creates an equality expression.
neq	Creates a disequality expression.
geq	Creates an inequality expression greater than or equal to.
leq	Creates an inequality expression less than or equal to.
gt	Creates an inequality expression greater than.
lt	Creates an inequality expression less than.
iif	Creates a ternary conditional expression.
abs	Creates an absolute value expression.
dist	Creates a distance expression.
div	Creates a division expression.
mod	Creates a modulo expression.
array	Creates an array expression.
at	Creates a “at” expression for N-dimensional array.
scalar	Creates an expression for the scalar product between two arrays.
ceil	Creates a ceil expression.
floor	Creates a floor expression.
round	Creates a rounding expression.
sqrt	Creates a square root expression.
log	Creates a log expression.
exp	Creates an exponential expression.
pow	Creates a power expression.
cos	Creates a cosine expression.
sin	Creates a sine expression.
tan	Creates a tangent expression.
piecewise	Creates a piecewise linear expression.
listVar	Creates a list decision with the given length.
setVar	Creates a set decision with the given length.
count	Creates a count expression.
indexOf	Creates an indexOf expression.
contains	Creates a contains expression.
partition	Creates a partition expression.
disjoint	Creates a disjoint expression.
nativeFunction	Creates a native function expression.
function	Creates a function expression.
range	Creates a range expression, where expr0 is the lower bound (inclusive) and expr1 is the upper bound (exclusive).
getNbExpressions	Gets the number of expressions added to this model.
getExpression	Gets the expression with the given index in this model.
getNbDecisions	Gets the number of decisions in the model.
getDecision	Gets the decision with the given index.
addConstraint	Adds the given expression to the list of constraints.
constraint	Shortcut for addConstraint(expr).
removeConstraint	Removes the given expression from the list of constraints.
getNbConstraints	Gets the number of constraints added to this model.
getConstraint	Gets the constraint with the given index.
addObjective	Adds the given expression to the list of objectives to optimize.
minimize	Shortcut for addObjective(expr, OD_Minimize).
maximize	Shortcut for addObjective(expr, OD_Maximize).
removeObjective	Removes the objective at the given position in the list of objectives.
getNbObjectives	Gets the number of objectives added to this model.
getObjective	Gets the objective with the given index.
getObjectiveDirection	Gets the direction of the objective with the given index.
getNbOperands	Gets the number of operands in the model.
close	Closes the model.
open	Reopens the model.
isClosed	Returns true if the model is closed, false otherwise.
toString	Returns a string representation of this model.

Functions¶

LSExpression createConstant(lsint value)¶

Creates a constant expression representing the given value.

Only allowed in state S_Modeling. Note that if a constant has been already created with the same value, this method can return the same expression, but it is not guaranteed. The exact behavior is implementation defined.

Return:	Created constant expression.
Parameters:	value - Value of the constant.

LSExpression createConstant(lsdouble value)¶

Creates a constant expression representing the given value.

Only allowed in state S_Modeling. Note that if a constant has been already created with the same value, this method can return the same expression, but it is not guaranteed. The exact behavior is implementation defined.

Return:	Created constant expression.
Parameters:	value - Value of the constant

template <typename... TN>

LSExpression createExpression(LSOperator op, TN... operands)¶

Creates an expression of the given type, with the given ordered operands.

Only allowed in state S_Modeling. The operands can be doubles, integers or previously declared LSExpressions. It is also possible to use this method with iterators. In that case, you have to call this method with 2 operands exactly that must be iterators of the same type, pointing respectively to the initial and final positions of the operands.

Return:	Created expression.
Templates:	TN - types of the operands to add. Types allowed: constant types, LSExpression or iterators.
Parameters:	op - Type of expression to create. operands - Operands.

LSExpression createNativeFunction(LSNativeFunction *func)¶

Creates a native function.

The argument must be derived from LSNativeFunction. When the native function is called, the argument values will be made accessible to your function through the native context.

Once you have instantiated it, you have to use call to call it in your model.

Return:	The expression associated to the function.
See:	LSNativeFunction
See:	O_NativeFunction
Since:	6.0
Parameters:	func - Native function to call.

template <typename... ARGS>

LSExpression createNativeFunction(const std::function<lsdouble(ARGS...)> &func)¶

Creates a native function.

The argument must be a std::function taking any combination of lsint and lsdouble arguments. When the native function is called, the argument values will be passed to your function as its arguments.

Once you have instantiated it, you have to use call to call it in your model.

Return:	The expression associated to the function.
See:	LSNativeFunction
See:	O_NativeFunction
Since:	8.0
Parameters:	func - std::function to call. It must only accept lsint and lsdouble arguments.

LSExpression createNativeFunction(const std::function<lsdouble(const LSNativeContext&)> &func)¶

Creates a native function.

The argument must be a std::function taking a single native context as its argument. When the native function is called, the argument values will be made accessible to your function through the native context.

Once you have instantiated it, you have to use call to call it in your model.

Return:	The expression associated to the function.
See:	LSNativeFunction
See:	O_NativeFunction
Since:	8.0
Parameters:	func - Native function to call.

template <typename A>

LSExpression createFunction(const A &functor)¶

Creates a function.

A function is a particular expression composed of two parts:

• The arguments of the function (which are also LSExpressions of type O_Argument)
• The body of the function. The body is an LSExpression that will be used to evaluate the result of the function. The body can be any LSExpression composed of any operands and operators supported by LocalSolver. Thus, the body expression can use the arguments of the function but can also capture and refer to expressions declared outside of the function.

You have to provide the body of the function as a std::function (C++ function or lambda). Please note that the provided std::function will not be used directly during the solving process, but will be evaluated once by the API with a number of LSExpression of type O_Argument that corresponds to the number of arguments your std::function expects. The returned LSExpression resulting of this evaluation will be used as the body of the LocalSolver function O_Function.

Return:	The expression associated to the function.
Since:	7.0
Parameters:	functor - Functor called to create the function.

LSExpression boolVar()¶

Creates a boolean decision.

Binary decision variable with domain { 0, 1 }. This method is a shortcut for createExpression(O_Bool).

See:	O_Bool
See:	createExpression
Since:	5.5

LSExpression floatVar(lsdouble lb, lsdouble ub)¶

Creates a float decision.

Decision variable with domain [lb, ub]. This method is a shortcut for createExpression(O_Float, lb, ub).

See:	O_Float
See:	createExpression
Since:	5.5
Parameters:	lb - Lower bound of the decision variable. ub - Upper bound of the decision variable.

LSExpression intVar(lsint lb, lsint ub)¶

Creates an integer decision.

Decision variable with domain [lb, ub]. This method is a shortcut for createExpression(O_Int, lb, ub).

See:	O_Int
See:	createExpression
Since:	5.5
Parameters:	lb - Lower bound of the decision variable. ub - Upper bound of the decision variable.

template <typename... TN>

LSExpression sum(TN... operands)¶

Creates a sum expression.

This method is a shortcut for createExpression(O_Sum, operands).

See:	O_Sum
See:	createExpression
Since:	5.5

template <typename T0, typename T1>

LSExpression sub(T0 expr0, T1 expr1)¶

Creates a substraction expression.

This method is a shortcut for createExpression(O_Sub, expr0, expr1).

See:	O_Sub
See:	createExpression
Since:	5.5

template <typename... TN>

LSExpression call(TN... operands)¶

Creates a call expression.

The first operand must be an LSExpression of type O_Function or O_NativeFunction. The other operands may be LSExpressions, booleans, integers, and doubles. They are passed to the function as arguments.

This method is a shortcut for createExpression(O_Call, operands).

See:	O_Call
See:	createExpression
Since:	6.0

template <typename... TN>

LSExpression prod(TN... operands)¶

Creates a product expression.

This method is a shortcut for createExpression(O_Prod, operands).

See:	O_Prod
See:	createExpression
Since:	5.5

template <typename... TN>

LSExpression max(TN... operands)¶

Creates a maximum expression.

This method is a shortcut for createExpression(O_Max, operands).

See:	O_Max
See:	createExpression
Since:	5.5

template <typename... TN>

LSExpression min(TN... operands)¶

Creates a minimum expression.

This method is a shortcut for createExpression(O_Min, operands).

See:	O_Min
See:	createExpression
Since:	5.5

template <typename... TN>

LSExpression or_(TN... operands)¶

Creates a OR expression.

This method is a shortcut for createExpression(O_Or, operands).

See:	O_Or
See:	createExpression
Since:	5.5

template <typename... TN>

LSExpression and_(TN... operands)¶

Creates an AND expression.

This method is a shortcut for createExpression(O_And, operands).

See:	O_And
See:	createExpression
Since:	5.5

template <typename... TN>

LSExpression xor_(TN... operands)¶

Creates a XOR expression.

This method is a shortcut for createExpression(O_Xor, operands).

See:	O_Xor
See:	createExpression
Since:	5.5

template <typename T0>

LSExpression not_(T0 expr0)¶

Creates a NOT expression.

This method is a shortcut for createExpression(O_Not, expr0).

See:	O_Not
See:	createExpression
Since:	5.5

template <typename T0, typename T1>

LSExpression eq(T0 expr0, T1 expr1)¶

Creates an equality expression.

This method is a shortcut for createExpression(O_Eq, expr0, expr1).

See:	O_Eq
See:	createExpression
Since:	5.5

template <typename T0, typename T1>

LSExpression neq(T0 expr0, T1 expr1)¶

Creates a disequality expression.

This method is a shortcut for createExpression(O_Neq, expr0, expr1).

See:	O_Neq
See:	createExpression
Since:	5.5

template <typename T0, typename T1>

LSExpression geq(T0 expr0, T1 expr1)¶

Creates an inequality expression greater than or equal to.

This method is a shortcut for createExpression(O_Geq, expr0, expr1).

See:	O_Geq
See:	createExpression
Since:	5.5

template <typename T0, typename T1>

LSExpression leq(T0 expr0, T1 expr1)¶

Creates an inequality expression less than or equal to.

This method is a shortcut for createExpression(O_Leq, expr0, expr1).

See:	O_Leq
See:	createExpression
Since:	5.5

template <typename T0, typename T1>

LSExpression gt(T0 expr0, T1 expr1)¶

Creates an inequality expression greater than.

This method is a shortcut for createExpression(O_Gt, expr0, expr1).

See:	O_Gt
See:	createExpression
Since:	5.5

template <typename T0, typename T1>

LSExpression lt(T0 expr0, T1 expr1)¶

Creates an inequality expression less than.

This method is a shortcut for createExpression(O_Lt, expr0, expr1).

See:	O_Lt
See:	createExpression
Since:	5.5

template <typename T0, typename T1, typename T2>

LSExpression iif(T0 condExpr, T1 trueExpr, T2 falseExpr)¶

Creates a ternary conditional expression.

This method is a shortcut for createExpression(O_If, condExpr, trueExpr, falseExpr).

See:	O_If
See:	createExpression
Since:	5.5

template <typename T0>

LSExpression abs(T0 expr0)¶

Creates an absolute value expression.

This method is a shortcut for createExpression(O_Abs, expr0).

See:	O_Abs
See:	createExpression
Since:	5.5

template <typename T0, typename T1>

LSExpression dist(T0 expr0, T1 expr1)¶

Creates a distance expression.

This method is a shortcut for createExpression(O_Dist, expr0, expr1).

See:	O_Dist
See:	createExpression
Since:	5.5

template <typename T0, typename T1>

LSExpression div(T0 expr0, T1 expr1)¶

Creates a division expression.

This method is a shortcut for createExpression(O_Div, expr0, expr1).

See:	O_Div
See:	createExpression
Since:	5.5

template <typename T0, typename T1>

LSExpression mod(T0 expr0, T1 expr1)¶

Creates a modulo expression.

This method is a shortcut for createExpression(O_Mod, expr0, expr1).

See:	O_Mod
See:	createExpression
Since:	5.5

template <typename... TN>

LSExpression array(TN... operands)¶

Creates an array expression.

This method is a shortcut for createExpression(O_Array, operands).

See:	O_Array
See:	createExpression
Since:	5.5

template <typename T0, typename... TN>

LSExpression at(T0 arrayExpr, TN... operands)¶

Creates a “at” expression for N-dimensional array.

This method is a shortcut for createExpression(O_At, arrayExpr, operands).

See:	O_At
See:	createExpression
Since:	5.5

template <typename T0, typename T1>

LSExpression scalar(T0 expr0, T1 expr1)¶

Creates an expression for the scalar product between two arrays.

This method is a shortcut for createExpression(O_Scalar, expr0, expr1).

See:	O_Scalar
See:	createExpression
Since:	5.5

template <typename T0>

LSExpression ceil(T0 expr0)¶

Creates a ceil expression.

This method is a shortcut for createExpression(O_Ceil, expr0).

See:	O_Ceil
See:	createExpression
Since:	5.5

template <typename T0>

LSExpression floor(T0 expr0)¶

Creates a floor expression.

This method is a shortcut for createExpression(O_Floor, expr0).

See:	O_Floor
See:	createExpression
Since:	5.5

template <typename T0>

LSExpression round(T0 expr0)¶

Creates a rounding expression.

This method is a shortcut for createExpression(O_Round, expr0).

See:	O_Round
See:	createExpression
Since:	5.5

template <typename T0>

LSExpression sqrt(T0 expr0)¶

Creates a square root expression.

This method is a shortcut for createExpression(O_Sqrt, expr0).

See:	O_Sqrt
See:	createExpression
Since:	5.5

template <typename T0>

LSExpression log(T0 expr0)¶

Creates a log expression.

This method is a shortcut for createExpression(O_Log, expr0).

See:	O_Log
See:	createExpression
Since:	5.5

template <typename T0>

LSExpression exp(T0 expr0)¶

Creates an exponential expression.

This method is a shortcut for createExpression(O_Exp, expr0).

See:	O_Exp
See:	createExpression
Since:	5.5

template <typename T0, typename T1>

LSExpression pow(T0 expr0, T1 expr1)¶

Creates a power expression.

This method is a shortcut for createExpression(O_Pow, expr0, expr1).

See:	O_Pow
See:	createExpression
Since:	5.5

template <typename T0>

LSExpression cos(T0 expr0)¶

Creates a cosine expression.

This method is a shortcut for createExpression(O_Cos, expr0).

See:	O_Cos
See:	createExpression
Since:	5.5

template <typename T0>

LSExpression sin(T0 expr0)¶

Creates a sine expression.

This method is a shortcut for createExpression(O_Sin, expr0).

See:	O_Sin
See:	createExpression
Since:	5.5

template <typename T0>

LSExpression tan(T0 expr0)¶

Creates a tangent expression.

This method is a shortcut for createExpression(O_Tan, expr0).

See:	O_Tan
See:	createExpression
Since:	5.5

template <typename T0, typename T1, typename T2>

LSExpression piecewise(T0 expr0, T1 expr1, T2 expr2)¶

Creates a piecewise linear expression.

This method is a shortcut for createExpression(O_Piecewise, expr, expr1, expr2).

See:	O_Piecewise
See:	createExpression
Since:	5.5

LSExpression listVar(lsint n)¶

Creates a list decision with the given length.

A list is a ordered collection of integers within a domain [0, n-1]. This method is a shortcut for createExpression(O_List, n).

See:	O_List
See:	createExpression
Since:	5.5

LSExpression setVar(lsint n)¶

Creates a set decision with the given length.

A set is a unordered collection of integers within a domain [0, n-1]. This method is a shortcut for createExpression(O_Set, n).

See:	O_Set
See:	createExpression
Since:	8.0

template <typename T0>

LSExpression count(T0 expr0)¶

Creates a count expression.

This method is a shortcut for createExpression(O_Count, expr0).

See:	O_Count
See:	createExpression
Since:	5.5

template <typename T0, typename T1>

LSExpression indexOf(T0 expr0, T1 expr1)¶

Creates an indexOf expression.

This method is a shortcut for createExpression(O_IndexOf, expr0, expr1).

See:	O_IndexOf
See:	createExpression
Since:	5.5

template <typename T0, typename T1>

LSExpression contains(T0 expr0, T1 expr1)¶

Creates a contains expression.

This method is a shortcut for createExpression(O_Contains, expr0, expr1).

See:	O_Contains
See:	createExpression
Since:	7.5

template <typename... TN>

LSExpression partition(TN... operands)¶

Creates a partition expression.

This method is a shortcut for createExpression(O_Partition, operands).

See:	O_Partition
See:	createExpression
Since:	5.5

template <typename... TN>

LSExpression disjoint(TN... operands)¶

Creates a disjoint expression.

This method is a shortcut for createExpression(O_Disjoint, operands).

See:	O_Disjoint
See:	createExpression
Since:	5.5

LSExpression nativeFunction(LSNativeFunction *func)¶

Creates a native function expression.

This method is a shortcut for createNativeFunction(func).

See:	O_NativeFunction
See:	createNativeFunction
Since:	6.0

template <typename... ARGS>

LSExpression nativeFunction(const std::function<lsdouble(ARGS...)> &func)¶

Creates a native function expression.

This method is a shortcut for createNativeFunction(func).

See:	O_NativeFunction
See:	createNativeFunction
Since:	8.0

LSExpression nativeFunction(const std::function<lsdouble(const LSNativeContext&)> &func)¶

Creates a native function expression.

This method is a shortcut for createNativeFunction(func).

See:	O_NativeFunction
See:	createNativeFunction
Since:	8.0

template <typename T>

LSExpression function(T functor)¶

Creates a function expression.

This method is a shortcut for createFunction(functor).

See:	O_Function
See:	createFunction
Since:	7.0

template <typename T0, typename T1>

LSExpression range(T0 expr0, T1 expr1)¶

Creates a range expression, where expr0 is the lower bound (inclusive) and expr1 is the upper bound (exclusive).

This method is a shortcut for createExpression(O_Range, expr0, expr1).

See:	O_Range
See:	createExpression
Since:	7.0

int getNbExpressions() const¶

Gets the number of expressions added to this model.

Return:	Number of expressions.

LSExpression getExpression(int exprIndex) const¶

Gets the expression with the given index in this model.

Return:	Expression with the given index.
Parameters:	exprIndex - Index of the expression.

LSExpression getExpression(const std::string &name) const¶

Gets the expression with the given name.

Throws an exception if no expression with the given name exists.

Return:	Expression with the given name.
Parameters:	name - Name.

int getNbDecisions() const¶

Gets the number of decisions in the model.

This corresponds to the number of decision variables declared in the model.

Return:	Number of decisions.

LSExpression getDecision(int decisionIndex) const¶

Gets the decision with the given index.

Return:	Decision with the given index.
Parameters:	decisionIndex - Index of the decision.

void addConstraint(const LSExpression &expr)¶

Adds the given expression to the list of constraints.

It means that the value of this expression must be constrained to be equal to 1 in any solution found by the solver. Hence, only boolean expressions (that is, expressions whose value is boolean) can be constrained. Only allowed in state S_Modeling. If the expression is already a constraint, this method does nothing and returns immediately.

Try to avoid hard constraints as much as possible, because LocalSolver (and more generally local search) is not suited for solving hardly constrained problems. In particular, banish constraints that are not surely satisfied in practice. Ideally, only combinatorial constraints (which induce the combinatorial structure of your problem) have to be set. All the other constraints can be relaxed as primary objectives in order to be “softly” satisfied (goal programming). For instance, constraint a <= b can be transformed into minimize max(b-a, 0).

Parameters:	expr - Expression.

void constraint(const LSExpression &expr)¶

Shortcut for addConstraint(expr).

See:	addConstraint
Since:	5.5
Parameters:	expr - Expression.

void removeConstraint(const LSExpression &expr)¶

Removes the given expression from the list of constraints.

If the expression was not constrained, this method does nothing and returns immediately. Only allowed in state S_Modeling.

Since:	5.0
Parameters:	expr - Expression.

void removeConstraint(int constraintIndex)¶

Removes the constraint at the given position in the list of constraints.

Only allowed in state S_Modeling.

Since:	5.0
Parameters:	constraintIndex - position of the constraint to remove.

int getNbConstraints() const¶

Gets the number of constraints added to this model.

Return:	Number of constraints.

LSExpression getConstraint(int constraintIndex) const¶

Gets the constraint with the given index.

Return:	Constraint with the given index.
Parameters:	constraintIndex - Index of the constraint.

void addObjective(const LSExpression &expr, LSObjectiveDirection direction)¶

Adds the given expression to the list of objectives to optimize.

The same expression can be added more than once. Only allowed in state S_Modeling. Note that the objectives will be optimized in the order in which they have been added to the model. It is useful for lexicographic multiobjective optimization, and more particularly for goal programming.

Parameters:	expr - Expression. direction - Optimization direction of this objective.

void minimize(const LSExpression &expr)¶

Shortcut for addObjective(expr, OD_Minimize).

See:	addObjective
Since:	5.5
Parameters:	expr - Expression.

void maximize(const LSExpression &expr)¶

Shortcut for addObjective(expr, OD_Maximize).

See:	addObjective
Since:	5.5
Parameters:	expr - Expression.

void removeObjective(int objectiveIndex) const¶

Removes the objective at the given position in the list of objectives.

Note that the objectives created after the removed one have their index decreased by 1. Phases are not modified when an objective is removed. It is the user’s responsibility to change the objective index of each phase to keep it coherent (with LSPhase#setOptimizedObjective), or to disable it (with LSPhase#setEnabled). Only allowed in state S_Modeling.

Since:	5.0
Parameters:	objectiveIndex - position of the objective to remove.

int getNbObjectives() const¶

Gets the number of objectives added to this model.

Return:	Number of objectives.

LSExpression getObjective(int objectiveIndex) const¶

Gets the objective with the given index.

Return:	Objective with the given index.
Parameters:	objectiveIndex - Index of the objective.

LSObjectiveDirection getObjectiveDirection(int objectiveIndex) const¶

Gets the direction of the objective with the given index.

Return:	Objective direction.
Parameters:	objectiveIndex - Index of the objective.

int getNbOperands() const¶

Gets the number of operands in the model.

This corresponds to the number of operands for all expressions declared in the model. It is an analog of the number of non zeros in matrix model encountered in mathematical programming: it gives an hint about the size and the density of your model.

Return:	Number of operands.

void close()¶

Closes the model.

Only allowed in state S_Modeling. When this method is called, the solver is placed in state S_Stopped.

Once the model is closed, no expressions, constraints or objectives can be added or removed unless the model is reopened. The model must be closed before starting its resolution.

void open()¶

Reopens the model.

Only allowed in state S_Stopped. When this method is called, the solver is placed in state S_Modeling.

In this state, the model can be modified: it is possible to add new expressions, constraints or objectives, modify expression operands, and remove existing constraints and objectives. However, existing expressions cannot be deleted.

bool isClosed() const¶

Returns true if the model is closed, false otherwise.

Return:	True if the model is closed.

std::string toString() const¶

Returns a string representation of this model.

This representation provides:

• The number of expressions, decisions, constraints, and objectives.
• The density of the model. Useful for debugging or logging purposes.

Return:	String representation.