HxExpression Class

class HxExpression

Mathematical modeling expression. Expressions are used to build the mathematical optimization model associated to a Hexaly Optimizer. An expression is composed of an operator (which corresponds to its type) and its operands (which are other expressions of the model).

See:HxModel
See:HxOperator

Summary

Functions
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.
isInterval Returns true if this expression is an interval, 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.
addOperand Add the given constant operand to this expression.
addOperand Add the given constant operand to this expression.
addOperand Add the given constant operand to this expression.
addOperands Add the given operands 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.
setOperand Replaces the operand of the given index.
setOperand Replaces the operand of 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 optimizer.
setValue Sets the value of this expression in the current solution found by the optimizer.
setValue Sets the value of this expression in the current solution found by the optimizer.
setIntValue Sets the value of this expression in the current solution found by the optimizer.
setDoubleValue Sets the value of this expression in the current solution found by the optimizer.
setIntervalValue Sets the value of this expression in the current solution found by the optimizer.
getValue Gets the value of this expression in the best solution found by the optimizer.
getIntValue Gets the value of this expression in the best solution found by the optimizer.
getDoubleValue Gets the value of this expression in the best solution found by the optimizer.
getIntervalValue Gets the value of this expression in the best solution found by the optimizer.
getCollectionValue Gets the value of this expression in the best solution found by the optimizer.
getArrayValue Gets the value of this expression in the best solution found by the optimizer.
getExternalContext Gets the external function context of this expression.
isViolated Returns true if the given expression is violated in the best solution found by the optimizer.
isUndefined Returns true if the given expression has an undefined value in the best solution found by the optimizer.
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.
Overloaded operators
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() Creates a O_Call expression with the given operands as arguments.

Functions

HxOperator HxExpression::getOperator() const

Gets the operator of this expression.

Returns:Operator.
int HxExpression::getIndex() const

Gets the index of this expression in the model.

Returns:Index in the model.
bool HxExpression::isConstant() const

Returns true if this expression is typed as constant in the model, false otherwise.

Returns:True if typed as constant.
bool HxExpression::isDecision() const

Returns true if this expression is typed as decision in the model, false otherwise.

Returns:True if typed as decision.
bool HxExpression::isConstraint() const

Returns true if this expression is tagged as constraint in the model, false otherwise.

Returns:True if tagged as constraint.
bool HxExpression::isObjective() const

Returns true if this expression is tagged as objective in the model, false otherwise.

Returns:True if tagged as objective.
bool HxExpression::isDouble() const

Returns true if this expression is a double, false otherwise. Only allowed in states S_Paused or S_Stopped.

Returns:True if the expression is a double.
Since:3.0
bool HxExpression::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.

Returns:True if the expression is an integer.
Since:3.0
bool HxExpression::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.

Returns:True if the expression is a boolean.
Since:3.0
bool HxExpression::isInterval() const

Returns true if this expression is an interval, false otherwise. Only allowed in states S_Paused or S_Stopped.

Returns:True if the expression is an interval.
Since:12.0
bool HxExpression::isArray() const

Returns true if this expression is an array, false otherwise. Only allowed in states S_Paused or S_Stopped.

Returns:True if the expression is an array.
Since:3.1
bool HxExpression::isCollection() const

Returns true if this expression is a collection (list or set), false otherwise. Only allowed in states S_Paused or S_Stopped.

Returns:True if the expression is a collection.
Since:5.5
bool HxExpression::isFunction() const

Returns true if this expression is a function, false otherwise. Only allowed in states S_Paused or S_Stopped.

Returns:True if the expression is a function.
Since:6.0
void HxExpression::addOperand(const HxExpression &operand)

Adds the given operand to this expression. Only allowed in state S_Modeling.

Parameters:operand – Operand to add.
void HxExpression::addOperand(int constant)

Add the given constant operand to this expression. Only allowed in state S_Modeling.

Parameters:constant – Constant operand to add.
void HxExpression::addOperand(hxint constant)

Add the given constant operand to this expression. Only allowed in state S_Modeling.

Parameters:constant – Constant operand to add.
void HxExpression::addOperand(hxdouble constant)

Add the given constant operand to this expression. Only allowed in state S_Modeling.

Parameters:constant – Constant operand to add.
Since:3.0
template<typename ...TN>
void HxExpression::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 HxExpressions. 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.

Parameters:
  • TN – types of the operands to add. Types allowed: constant types, HxExpression or iterators.
  • operands – operands.
template<typename T0, typename T1>
void HxExpression::addOperands(T0 begin, T1 end)

Add the given operands to this expression. Only allowed in state S_Modeling.

Parameters:
  • begin – iterator to the initial position of the operands to add.
  • end – iterator to the final position of the operands to add.
Since:

5.5
HxExpression HxExpression::getOperand(int operandIndex) const

Gets the operand with the given index.

Parameters:operandIndex – Index of the operand.
Returns:Operand.
void HxExpression::setOperand(int operandIndex, const HxExpression &operand)

Replaces the operand of the given index.

Parameters:
  • operandIndex – Index of the operand to change
  • operand – New operand
void HxExpression::setOperand(int operandIndex, int constant)

Replaces the operand of the given index.

Parameters:
  • operandIndex – Index of the operand to change.
  • constant – New constant operand.
void HxExpression::setOperand(int operandIndex, hxint constant)

Replaces the operand of the given index.

Parameters:
  • operandIndex – Index of the operand to change.
  • constant – New constant operand.
void HxExpression::setOperand(int operandIndex, hxdouble constant)

Replaces the operand of the given index.

Parameters:
  • operandIndex – Index of the operand to change.
  • constant – New constant operand.
Since:

3.0
int HxExpression::getNbOperands() const

Gets the number of operands of this expression.

Returns:Number of operands.
void HxExpression::setValue(hxint value)

Sets the value of this expression in the current solution found by the optimizer. Only allowed for decisions. Only allowed in state S_Stopped. Only allowed if this expression is an integer or a boolean. If the optimizer was not launched, this value will be used as an initial value for the decision. This method is a shortcut for HxSolution::setValue() and has the same behavior as setIntValue().

Parameters:value – Value assigned to this expression.
See:HxSolution::setValue()
See:HxExpression::isInt()
See:HxExpression::isBool()
void HxExpression::setValue(hxdouble value)

Sets the value of this expression in the current solution found by the optimizer. Only allowed for decisions. Only allowed in state S_Stopped. Only allowed if this expression is an integer or a boolean. If the optimizer was not launched, this value will be used as an initial value for the decision. This method is a shortcut for HxSolution::setDoubleValue() and has the same behavior as setDoubleValue().

Parameters:value – Value assigned to this expression.
See:HxSolution::setValue()
See:HxExpression::isDouble()
void HxExpression::setValue(hxinterval value)

Sets the value of this expression in the current solution found by the optimizer. Only allowed for decisions. Only allowed in state S_Stopped. Only allowed if this expression is an interval If the optimizer was not launched, this value will be used as an initial value for the decision. This method is a shortcut for HxSolution::setIntervalValue() and has the same behavior as setIntervalValue().

Parameters:value – Value assigned to this expression.
See:HxSolution::setValue()
See:HxExpression::isInterval()
void HxExpression::setIntValue(hxint value)

Sets the value of this expression in the current solution found by the optimizer. Only allowed for decisions. Only allowed in state S_Stopped. Only allowed if this expression is an integer or a boolean. If the optimizer was not launched, this value will be used as an initial value for the decision. This method is a shortcut for HxSolution::setIntValue().

Parameters:value – Value assigned to this expression.
See:HxSolution::setIntValue()
See:HxExpression::isInt()
See:HxExpression::isBool()
Since:3.0
void HxExpression::setDoubleValue(hxdouble value)

Sets the value of this expression in the current solution found by the optimizer. Only allowed for decisions. Only allowed in state S_Stopped. Only allowed if this expression is a double. If the optimizer was not launched, this value will be used as an initial value for the decision. This method is a shortcut for HxSolution::setDoubleValue().

Parameters:value – Value assigned to this expression.
See:HxSolution::setDoubleValue()
See:HxExpression::isDouble()
Since:3.0
void HxExpression::setIntervalValue(hxinterval value)

Sets the value of this expression in the current solution found by the optimizer. Only allowed for decisions. Only allowed in state S_Stopped. Only allowed if this expression is an interval. If the optimizer was not launched, this value will be used as an initial value for the decision. This method is a shortcut for HxSolution::setIntervalValue().

Parameters:value – Value assigned to this expression.
See:HxSolution::setIntervalValue()
See:HxExpression::isInterval()
Since:12.0
hxint HxExpression::getValue() const

Gets the value of this expression in the best solution found by the optimizer. 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 HxSolution::getValue().

Returns:Value in the best solution.
See:HxSolution::getValue()
See:HxExpression::isInt()
See:HxExpression::isBool()
hxint HxExpression::getIntValue() const

Gets the value of this expression in the best solution found by the optimizer. 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 HxSolution::getIntValue().

Returns:Value in the best solution.
See:HxSolution::getIntValue()
See:HxExpression::isInt()
See:HxExpression::isBool()
Since:3.0
hxdouble HxExpression::getDoubleValue() const

Gets the value of this expression in the best solution found by the optimizer. Only allowed in states S_Paused or S_Stopped. Only allowed if this expression is a double. This method is a shortcut for HxSolution::getDoubleValue().

Returns:Value in the best solution.
See:HxSolution::getDoubleValue()
See:HxExpression::isDouble()
Since:3.0
hxinterval HxExpression::getIntervalValue() const

Gets the value of this expression in the best solution found by the optimizer. Only allowed in states S_Paused or S_Stopped. Only allowed if this expression is an interval. This method is a shortcut for HxSolution::getIntervalValue().

Returns:Value in the best solution.
See:HxSolution::getIntervalValue()
See:HxExpression::isInterval()
Since:12.0
HxCollection HxExpression::getCollectionValue() const

Gets the value of this expression in the best solution found by the optimizer. 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 HxSolution::getCollectionValue().

Returns:Value in the best solution.
See:HxExpression::isCollection()
See:HxSolution::getCollectionValue()
Since:5.5
HxArray HxExpression::getArrayValue() const

Gets the value of this expression in the best solution found by the optimizer. Only allowed in states S_Paused or S_Stopped. Only allowed if this expression is an array. This method is a shortcut for HxSolution::getArrayValue().

Returns:Value in the best solution.
See:HxExpression::isArray()
See:HxSolution::getArrayValue()
Since:7.5
HxExternalContext HxExpression::getExternalContext() const

Gets the external function context of this expression. Only allowed if this expression is an external function.

Returns:Context of the external function.
See:HxExternalContext
Since:9.5
bool HxExpression::isViolated() const

Returns true if the given expression is violated in the best solution found by the optimizer. An expression can be violated in 3 cases:

  1. it is a constraint and its value is 0
  2. it is a double objective and its value is NaN (Not a Number)
  3. it is an integer or boolean with no valid value (arithmetic or out of bounds exception).

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 HxSolution::isViolated().

Returns:True if this expression is violated in the best solution.
Since:5.5
See:HxExpression::isUndefined()
bool HxExpression::isUndefined() const

Returns true if the given expression has an undefined value in the best solution found by the optimizer. An expression can be undefined in 4 cases:

  • It is a double and its value is NaN (Not a Number).
  • It is an integer or boolean with no valid value (arithmetic or out of bounds exception).
  • It is an interval with at least one undefined bound.
  • It is the result of any ill-defined operation (at with out of bounds index or operations on undefined values for instance).

Only allowed in states S_Paused or S_Stopped. This method is a shortcut for HxSolution::isUndefined().

Returns:True if this expression has an undefined value in the best solution.
Since:7.0
void HxExpression::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 HxExpression::isNamed() const

Returns true if this expression has a name, and false otherwise.

Returns:True if named.
std::string HxExpression::getName() const

Gets the name of this expression or the empty string if no name has been set.

Returns:Name.
std::string HxExpression::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.

Returns:String representation.

Overloaded operators

template<typename T>
HxExpression HxExpression::operator+(T operand)

Creates a new O_Sum expression. It is a shortcut for model.createExpression(O_Sum, this, operand).

Parameters:operand – Operand. Can be an HxExpression, an integer or a double.
Returns:A new O_Sum expression.
template<typename T>
HxExpression HxExpression::operator-(T operand)

Creates a new O_Sub expression. It is a shortcut for model.createExpression(O_Sub, this, operand).

Parameters:operand – Operand. Can be an HxExpression, an integer or a double.
Returns:A new O_Sub expression.
template<typename T>
HxExpression HxExpression::operator*(T operand)

Creates a new O_Prod expression. It is a shortcut for model.createExpression(O_Prod, this, operand).

Parameters:operand – Operand. Can be an HxExpression, an integer or a double.
Returns:A new O_Prod expression.
template<typename T>
HxExpression HxExpression::operator%(T operand)

Creates a new O_Mod expression. It is a shortcut for model.createExpression(O_Mod, this, operand).

Parameters:operand – Operand. Can be an HxExpression or an integer.
Returns:A new O_Mod expression.
template<typename T>
HxExpression HxExpression::operator/(T operand)

Creates a new O_Div expression. It is a shortcut for model.createExpression(O_Div, this, operand).

Parameters:operand – Operand. Can be an HxExpression, an integer or a double.
Returns:A new O_Div expression.
HxExpression HxExpression::operator!()

Creates a new O_Not expression. It is a shortcut for model.createExpression(O_Not, this).

Returns:A new O_Not expression.
template<typename T>
HxExpression HxExpression::operator&&(T operand)

Creates a new O_And expression. It is a shortcut for model.createExpression(O_And, this, operand).

Parameters:operand – Operand. Can be an HxExpression or a boolean.
Returns:A new O_And expression.
template<typename T>
HxExpression HxExpression::operator||(T operand)

Creates a new O_Or expression. It is a shortcut for model.createExpression(O_Or, this, operand).

Parameters:operand – Operand. Can be an HxExpression or a boolean.
Returns:A new O_Or expression.
template<typename T>
HxExpression HxExpression::operator^(T operand)

Creates a new O_Xor expression. It is a shortcut for model.createExpression(O_Xor, this, operand).

Parameters:operand – Operand. Can be an HxExpression or a boolean.
Returns:A new O_Xor expression.
template<typename T>
HxExpression HxExpression::operator==(T operand)

Creates a new O_Eq expression. It is a shortcut for model.createExpression(O_Eq, this, operand).

Parameters:operand – Operand. Can be an HxExpression, an integer or a double.
Returns:A new O_Eq expression.
template<typename T>
HxExpression HxExpression::operator!=(T operand)

Creates a new O_Neq expression. It is a shortcut for model.createExpression(O_Neq, this, operand).

Parameters:operand – Operand. Can be an HxExpression, an integer or a double.
Returns:A new O_Neq expression.
template<typename T>
HxExpression HxExpression::operator>=(T operand)

Creates a new O_Geq expression. It is a shortcut for model.createExpression(O_Geq, this, operand).

Parameters:operand – Operand. Can be an HxExpression, an integer or a double.
Returns:A new O_Geq expression.
template<typename T>
HxExpression HxExpression::operator<=(T operand)

Creates a new O_Leq expression. It is a shortcut for model.createExpression(O_Leq, this, operand).

Parameters:operand – Operand. Can be an HxExpression, an integer or a double.
Returns:A new O_Leq expression.
template<typename T>
HxExpression HxExpression::operator>(T operand)

Creates a new O_Gt expression. It is a shortcut for model.createExpression(O_Gt, this, operand).

Parameters:operand – Operand. Can be an HxExpression, an integer or a double.
Returns:A new O_Gt expression.
template<typename T>
HxExpression HxExpression::operator<(T operand)

Creates a new O_Lt expression. It is a shortcut for model.createExpression(O_Lt, this, operand).

Parameters:operand – Operand. Can be an HxExpression, an integer or a double.
Returns:A new O_Lt expression.
template<typename T>
HxExpression HxExpression::operator[](T operand)

Creates a new O_At expression. It is a shortcut for model.createExpression(O_At, this, operand).

Parameters:operand – Operand. Can be an HxExpression, an integer or a double.
Returns:A new O_At expression.
template<typename ...TN>
HxExpression HxExpression::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).

Parameters:
  • TN – types of the operands to add. Types allowed: constant types, HxExpression or iterators.
  • operands – operands.