LSExpression Class¶

class
localsolver::
LSExpression
¶ Mathematical modeling expression.
Expressions are used to build the mathematical optimization model associated to LocalSolver. An expression is composed of an operator (which corresponds to its type) and its operands (which are other expressions of the model).
See: LSModel See: LSOperator
Summary¶
getOperator 
Gets the operator of this expression. 
getIndex 
Gets the index of this expression in the model. 
isConstant 
Returns true if this expression is typed as constant in the model, false otherwise. 
isDecision 
Returns true if this expression is typed as decision in the model, false otherwise. 
isConstraint 
Returns true if this expression is tagged as constraint in the model, false otherwise. 
isObjective 
Returns true if this expression is tagged as objective in the model, false otherwise. 
isDouble 
Returns true if this expression is a double, false otherwise. 
isInt 
Returns true if this expression is an integer, false otherwise. 
isBool 
Returns true if this expression is a boolean (ie 0 or 1), false otherwise. 
isArray 
Returns true if this expression is an array, false otherwise. 
isCollection 
Returns true if this expression is a collection (list or set), false otherwise. 
isFunction 
Returns true if this expression is a function, false otherwise. 
addOperand 
Adds the given operand to this expression. 
addOperands 
Add the given operands to this expression. 
getOperand 
Gets the operand with the given index. 
setOperand 
Replaces the operand of the given index. 
getNbOperands 
Gets the number of operands of this expression. 
setValue 
Sets the value of this expression in the current solution found by the solver. 
setIntValue 
Sets the value of this expression in the current solution found by the solver. 
setDoubleValue 
Sets the value of this expression in the current solution found by the solver. 
getValue 
Gets the value of this expression in the best solution found by the solver. 
getIntValue 
Gets the value of this expression in the best solution found by the solver. 
getDoubleValue 
Gets the value of this expression in the best solution found by the solver. 
getCollectionValue 
Gets the value of this expression in the best solution found by the solver. 
getArrayValue 
Gets the value of this expression in the best solution found by the solver. 
isViolated 
Returns true if the given expression is violated in the best solution found by the solver. 
isUndefined 
Returns true if the given expression has an undefined value in the best solution found by the solver. 
setName 
Sets the name of this expression. 
isNamed 
Returns true if this expression has a name, and false otherwise. 
getName 
Gets the name of this expression or the empty string if no name has been set. 
toString 
Returns a string representation of this expression. 
getInfo 
Returns useful info about this expression (according to the state of LocalSolver). 
operator+ 
Creates a new O_Sum expression. 
operator 
Creates a new O_Sub expression. 
operator* 
Creates a new O_Prod expression. 
operator% 
Creates a new O_Mod expression. 
operator/ 
Creates a new O_Div expression. 
operator! 
Creates a new O_Not expression. 
operator&& 
Creates a new O_And expression. 
operator 
Creates a new O_Or expression. 
operator^ 
Creates a new O_Xor expression. 
operator== 
Creates a new O_Eq expression. 
operator!= 
Creates a new O_Neq expression. 
operator>= 
Creates a new O_Geq expression. 
operator<= 
Creates a new O_Leq expression. 
operator> 
Creates a new O_Gt expression. 
operator< 
Creates a new O_Lt expression. 
operator[] 
Creates a new O_At expression. 
operator+= 
Sums the given operand with the current expression. 
operator*= 
Multiply the given operand with the current expression. 
operator&= 
Creates a logical AND between the current expression and the given operand. 
operator^= 
Creates a logical XOR between the current expression and the given operand. 
operator= 
Creates a logical OR between the current expression and the given operand. 
operator() 
Creates a O_Call expression with the given operands as arguments. 
Functions¶

LSOperator
getOperator
() const¶ Gets the operator of this expression.
Return: Operator.

int
getIndex
() const¶ Gets the index of this expression in the model.
Return: Index in the model.

bool
isConstant
() const¶ Returns true if this expression is typed as constant in the model, false otherwise.
Return: True if typed as constant.

bool
isDecision
() const¶ Returns true if this expression is typed as decision in the model, false otherwise.
Return: True if typed as decision.

bool
isConstraint
() const¶ Returns true if this expression is tagged as constraint in the model, false otherwise.
Return: True if tagged as constraint.

bool
isObjective
() const¶ Returns true if this expression is tagged as objective in the model, false otherwise.
Return: True if tagged as objective.

bool
isDouble
() const¶ Returns true if this expression is a double, false otherwise.
Only allowed in states S_Paused or S_Stopped.
Return: True if the expression is a double. Since: 3.0

bool
isInt
() const¶ Returns true if this expression is an integer, false otherwise.
Only allowed in states S_Paused or S_Stopped. Note that a boolean is also an integer.
Return: True if the expression is an integer. Since: 3.0

bool
isBool
() const¶ Returns true if this expression is a boolean (ie 0 or 1), false otherwise.
Only allowed in states S_Paused or S_Stopped.
Return: True if the expression is a boolean. Since: 3.0

bool
isArray
() const¶ Returns true if this expression is an array, false otherwise.
Only allowed in states S_Paused or S_Stopped.
Return: True if the expression is an array. Since: 3.1

bool
isCollection
() const¶ Returns true if this expression is a collection (list or set), false otherwise.
Only allowed in states S_Paused or S_Stopped.
Return: True if the expression is a collection. Since: 5.5

bool
isFunction
() const¶ Returns true if this expression is a function, false otherwise.
Only allowed in states S_Paused or S_Stopped.
Return: True if the expression is a function. Since: 6.0

void
addOperand
(const LSExpression &expr)¶ Adds the given operand to this expression.
Only allowed in state S_Modeling.
Parameters: expr  Operand to add.

void
addOperand
(int constant)¶ Add the given constant operand to this expression.
Only allowed in state S_Modeling.
Parameters: constant  Constant operand to add.

void
addOperand
(lsint constant)¶ Add the given constant operand to this expression.
Only allowed in state S_Modeling.
Parameters: constant  Constant operand to add.

void
addOperand
(lsdouble constant)¶ Add the given constant operand to this expression.
Only allowed in state S_Modeling.
Since: 3.0 Parameters: constant  Constant operand to add.
 template <typename... TN>

void
addOperands
(TN... operands)¶ Add the given operands to this expression.
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 arguments exactly that must be iterators of the same type, pointing respectively to the initial and final positions of the operands.
Templates: TN  types of the operands to add. Types allowed: constant types, LSExpression or iterators. Parameters: operands  operands.
 template <typename T0, typename T1>

void
addOperands
(T0 begin, T1 end)¶ Add the given operands to this expression.
Only allowed in state S_Modeling.
Since: 5.5
Parameters:  begin  iterator to the initial position of the operands to add.
 end  iterator to the final position of the operands to add.

LSExpression
getOperand
(int operandIndex) const¶ Gets the operand with the given index.
Return: Operand. Parameters: operandIndex  Index of the operand.

void
setOperand
(int operandIndex, LSExpression operand)¶ Replaces the operand of the given index.
Parameters:  operandIndex  Index of the operand to change
 operand  New operand

void
setOperand
(int operandIndex, lsint constant)¶ Replaces the operand of the given index.
Parameters:  operandIndex  Index of the operand to change.
 constant  New constant operand.

void
setOperand
(int operandIndex, lsdouble constant)¶ Replaces the operand of the given index.
Since: 3.0
Parameters:  operandIndex  Index of the operand to change.
 constant  New constant operand.

int
getNbOperands
() const¶ Gets the number of operands of this expression.
Return: Number of operands.

void
setValue
(lsint value)¶ Sets the value of this expression in the current solution found by the solver.
Only allowed for decisions. Only allowed in state S_Stopped. Only allowed if this expression is an integer or a boolean. If the solver was not launched, this value will be used as an initial value for the decision. This method is a shortcut for LSSolution#setValue(const LSExpression&, lsint) and has the same behavior as setIntValue(lsint).
See: LSSolution::setValue(const LSExpression&, lsint) See: isInt() See: isBool() Parameters: value  Value assigned to this expression.

void
setValue
(lsdouble value)¶ Sets the value of this expression in the current solution found by the solver.
Only allowed for decisions. Only allowed in state S_Stopped. Only allowed if this expression is an integer or a boolean. If the solver was not launched, this value will be used as an initial value for the decision. This method is a shortcut for LSSolution#setValue(const LSExpression&, lsdouble) and has the same behavior as setDoubleValue(lsdouble).
See: LSSolution::setValue(const LSExpression &expr, lsdouble value) See: isDouble() Parameters: value  Value assigned to this expression.

void
setIntValue
(lsint value)¶ Sets the value of this expression in the current solution found by the solver.
Only allowed for decisions. Only allowed in state S_Stopped. Only allowed if this expression is an integer or a boolean. If the solver was not launched, this value will be used as an initial value for the decision. This method is a shortcut for LSSolution#setValue(const LSExpression&, lsint).
See: LSSolution::setIntValue(const LSExpression&, lsint) See: isInt() See: isBool() Since: 3.0 Parameters: value  Value assigned to this expression.

void
setDoubleValue
(lsdouble value)¶ Sets the value of this expression in the current solution found by the solver.
Only allowed for decisions. Only allowed in state S_Stopped. Only allowed if this expression is a double. If the solver was not launched, this value will be used as an initial value for the decision. This method is a shortcut for LSSolution#setValue(const LSExpression&, lsdouble).
See: LSSolution::setDoubleValue(const LSExpression&, lsdouble) See: isDouble() Since: 3.0 Parameters: value  Value assigned to this expression.

lsint
getValue
() const¶ Gets the value of this expression in the best solution found by the solver.
Only allowed in states S_Paused or S_Stopped. Only allowed if this expression is an integer or a boolean. This method is a shortcut for LSSolution#getValue(const LSExpression&).
Return: Value in the best solution. See: LSSolution::getValue(const LSExpression&) See: isInt() See: isBool()

lsint
getIntValue
() const¶ Gets the value of this expression in the best solution found by the solver.
Only allowed in states S_Paused or S_Stopped. Only allowed if this expression is an integer or a boolean. This method is a shortcut for LSSolution#getIntValue(const LSExpression&).
Return: Value in the best solution. See: LSSolution::getIntValue(const LSExpression&) See: isInt() See: isBool() Since: 3.0

lsdouble
getDoubleValue
() const¶ Gets the value of this expression in the best solution found by the solver.
Only allowed in states S_Paused or S_Stopped. Only allowed if this expression is a double. This method is a shortcut for LSSolution#getDoubleValue(const LSExpression&).
Return: Value in the best solution. See: LSSolution::getDoubleValue(const LSExpression&) See: isDouble() Since: 3.0

LSCollection
getCollectionValue
() const¶ Gets the value of this expression in the best solution found by the solver.
Only allowed in states S_Paused or S_Stopped. Only allowed if this expression is a collection (list or set). This method is a shortcut for LSSolution#getCollectionValue(const LSExpression&).
Return: Value in the best solution. See: LSExpression::isCollection See: LSSolution::getCollectionValue(const LSExpression&) Since: 5.5

LSArray
getArrayValue
() const¶ Gets the value of this expression in the best solution found by the solver.
Only allowed in states S_Paused or S_Stopped. Only allowed if this expression is an array. This method is a shortcut for LSSolution#getArrayValue(const LSExpression&).
Return: Value in the best solution. See: LSExpression::isArray See: LSSolution::getArrayValue(const LSExpression&) Since: 7.5

bool
isViolated
() const¶ Returns true if the given expression is violated in the best solution found by the solver.
An expression can be violated in 3 cases:
 it is a constraint and its value is 0
 it is a a double objective and its value is NaN (NotANumber)
 it is a constraint with no valid value (arithmetic or out of bounds exception or NaN operands). Note that only constraints and objectives can be violated. Other expression can have undefined value provided that it does not impact a constraint or objective.
Only allowed in states S_Paused or S_Stopped. This method is a shortcut for LSSolution#isViolated().
Return: True if this expression is violated in the best solution. Since: 5.5 See: isUndefined()

bool
isUndefined
() const¶ Returns true if the given expression has an undefined value in the best solution found by the solver.
An expression can be undefined in 2 cases:
 it is a a double and its value is NaN (NotANumber)
 it is an integer or boolean with no valid value (arithmetic or out of bounds exception). Only allowed in states S_Paused or S_Stopped. This method is a shortcut for LSSolution#isUndefined(const LSExpression&).
Return: True if this expression has an undefined value in the best solution. Since: 7.0

void
setName
(const std::string &name)¶ Sets the name of this expression.
Only allowed in state S_Modeling. The name cannot be empty. Two operators of the model cannot share the same name. Useful for debugging or logging purposes.
Parameters: name  Name.

bool
isNamed
() const¶ Returns true if this expression has a name, and false otherwise.
Return: True if named.

const std::string
getName
() const¶ Gets the name of this expression or the empty string if no name has been set.
Return: Name.

std::string
toString
() const¶ Returns a string representation of this expression.
This representation provides the index of the expression, its type, and its name (if any). Useful for debugging or logging purposes.
Return: String representation.

std::string
getInfo
() const¶ Returns useful info about this expression (according to the state of LocalSolver).
Useful for debugging or logging purposes.
Return: Info about this search during the solving process.
 template <typename T>

LSExpression
operator+
(T operand)¶ Creates a new O_Sum expression.
It is a shortcut for
model.createExpression(O_Sum, this, operand)
.Return: A new O_Sum expression. Parameters: operand  Operand. Can be an LSExpression, an integer or a double.
 template <typename T>

LSExpression
operator
(T operand)¶ Creates a new O_Sub expression.
It is a shortcut for
model.createExpression(O_Sub, this, operand)
.Return: A new O_Sub expression. Parameters: operand  Operand. Can be an LSExpression, an integer or a double.
 template <typename T>

LSExpression
operator*
(T operand)¶ Creates a new O_Prod expression.
It is a shortcut for
model.createExpression(O_Prod, this, operand)
.Return: A new O_Prod expression. Parameters: operand  Operand. Can be an LSExpression, an integer or a double.
 template <typename T>

LSExpression
operator%
(T operand)¶ Creates a new O_Mod expression.
It is a shortcut for
model.createExpression(O_Mod, this, operand)
.Return: A new O_Mod expression. Parameters: operand  Operand. Can be an LSExpression or an integer.
 template <typename T>

LSExpression
operator/
(T operand)¶ Creates a new O_Div expression.
It is a shortcut for
model.createExpression(O_Div, this, operand)
.Return: A new O_Div expression. Parameters: operand  Operand. Can be an LSExpression, an integer or a double.

LSExpression
operator!
()¶ Creates a new O_Not expression.
It is a shortcut for
model.createExpression(O_Not, this)
.Return: A new O_Not expression.
 template <typename T>

LSExpression
operator&&
(T operand)¶ Creates a new O_And expression.
It is a shortcut for
model.createExpression(O_And, this, operand)
.Return: A new O_And expression. Parameters: operand  Operand. Can be an LSExpression or a boolean.
 template <typename T>

LSExpression
operator
(T operand)¶ Creates a new O_Or expression.
It is a shortcut for
model.createExpression(O_Or, this, operand)
.Return: A new O_Or expression. Parameters: operand  Operand. Can be an LSExpression or a boolean.
 template <typename T>

LSExpression
operator^
(T operand)¶ Creates a new O_Xor expression.
It is a shortcut for
model.createExpression(O_Xor, this, operand)
.Return: A new O_Xor expression. Parameters: operand  Operand. Can be an LSExpression or a boolean.
 template <typename T>

LSExpression
operator==
(T operand)¶ Creates a new O_Eq expression.
It is a shortcut for
model.createExpression(O_Eq, this, operand)
.Return: A new O_Eq expression. Parameters: operand  Operand. Can be an LSExpression, an integer or a double.
 template <typename T>

LSExpression
operator!=
(T operand)¶ Creates a new O_Neq expression.
It is a shortcut for
model.createExpression(O_Neq, this, operand)
.Return: A new O_Neq expression. Parameters: operand  Operand. Can be an LSExpression, an integer or a double.
 template <typename T>

LSExpression
operator>=
(T operand)¶ Creates a new O_Geq expression.
It is a shortcut for
model.createExpression(O_Geq, this, operand)
.Return: A new O_Geq expression. Parameters: operand  Operand. Can be an LSExpression, an integer or a double.
 template <typename T>

LSExpression
operator<=
(T operand)¶ Creates a new O_Leq expression.
It is a shortcut for
model.createExpression(O_Leq, this, operand)
.Return: A new O_Leq expression. Parameters: operand  Operand. Can be an LSExpression, an integer or a double.
 template <typename T>

LSExpression
operator>
(T operand)¶ Creates a new O_Gt expression.
It is a shortcut for
model.createExpression(O_Gt, this, operand)
.Return: A new O_Gt expression. Parameters: operand  Operand. Can be an LSExpression, an integer or a double.
 template <typename T>

LSExpression
operator<
(T operand)¶ Creates a new O_Lt expression.
It is a shortcut for
model.createExpression(O_Lt, this, operand)
.Return: A new O_Lt expression. Parameters: operand  Operand. Can be an LSExpression, an integer or a double.
 template <typename T>

LSExpression
operator[]
(T operand)¶ Creates a new O_At expression.
It is a shortcut for
model.createExpression(O_At, this, operand)
.Return: A new O_At expression. Parameters: operand  Operand. Can be an LSExpression, an integer or a double.
 template <typename T>

LSExpression
operator+=
(T operand)¶ Sums the given operand with the current expression.
If the current expression is already of type O_Sum, the given operand is simply pushed on the current list of operands. A new O_Sum expression is created otherwise.
Return: Return the current expression or a new O_Sum expression. Parameters: operand  Operand. Can be an LSExpression, an integer or a double.
 template <typename T>

LSExpression
operator*=
(T operand)¶ Multiply the given operand with the current expression.
If the current expression is already of type O_Prod, the given operand is simply pushed on the current list of operands. A new O_Prod expression is created otherwise.
Return: Return the current expression or a new O_Prod expression. Parameters: operand  Operand. Can be an LSExpression, an integer or a double.
 template <typename T>

LSExpression
operator&=
(T operand)¶ Creates a logical AND between the current expression and the given operand.
If the current expression is already of type O_And, the given operand is simply pushed on the current list of operands. A new O_And expression is created otherwise.
Return: Return the current expression or a new O_And expression. Parameters: operand  Operand. Can be an LSExpression or a boolean.
 template <typename T>

LSExpression
operator^=
(T operand)¶ Creates a logical XOR between the current expression and the given operand.
If the current expression is already of type O_Xor, the given operand is simply pushed on the current list of operands. A new O_Xor expression is created otherwise.
Return: Return the current expression or a new O_Xor expression. Parameters: operand  Operand. Can be an LSExpression or a boolean.
 template <typename T>

LSExpression
operator=
(T operand)¶ Creates a logical OR between the current expression and the given operand.
If the current expression is already of type O_Or, the given operand is simply pushed on the current list of operands. A new O_Or expression is created otherwise.
Return: Return the current expression or a new O_Or expression. Parameters: operand  Operand. Can be an LSExpression or a boolean.
 template <typename... TN>

LSExpression
operator()
(TN... operands)¶ Creates a O_Call expression with the given operands as arguments.
It is a shortcut for
model.createExpression(O_Call, this, operands)
.Templates: TN  types of the operands to add. Types allowed: constant types, LSExpression or iterators. Parameters: operands  operands.