localsolver

Class LSExpression

java.lang.Object

localsolver.LSExpression

public class LSExpression
extends java.lang.Object

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 Also:

LSModel, LSOperator

Method Summary

Methods

Modifier and Type	Method and Description
void	addOperand(double constant) Add the given constant operand to this expression.
void	addOperand(long constant) Add the given constant operand to this expression.
void	addOperand(LSExpression expr) Adds the given operand to this expression.
void	addOperands(double... operands) Add the given constant double operands to this expression.
void	addOperands(java.lang.Iterable<LSExpression> operands) Add the given operands to this expression.
void	addOperands(long... operands) Add the given constant integer operands to this expression.
void	addOperands(LSExpression... operands) Add the given operands to this expression.
boolean	equals(java.lang.Object obj)
LSCollection	getCollectionValue() Gets the value of this expression in the best solution found by the solver.
double	getDoubleValue() Gets the value of this expression in the best solution found by the solver.
int	getIndex() Gets the index of this expression in the model.
java.lang.String	getInfo() Returns useful info about this expression (according to the state of LocalSolver).
long	getIntValue() Gets the value of this expression in the best solution found by the solver.
LocalSolver	getLocalSolver()
LSModel	getModel()
java.lang.String	getName() Gets the name of this expression or the empty String if no name has been set.
int	getNbOperands() Gets the number of operands of this expression.
LSExpression	getOperand(int operandIndex) Gets the operand with the given index.
LSOperator	getOperator() Gets the operator of this expression.
long	getValue() Gets the value of this expression in the best solution found by the solver.
int	hashCode()
boolean	isArray() Returns true if this expression is an array, false otherwise.
boolean	isBool() Returns true if this expression is a boolean (ie 0 or 1), false otherwise.
boolean	isCollection() Returns true if this expression is a collection, false otherwise.
boolean	isConstant() Returns true if this expression is typed as constant in the model, false otherwise.
boolean	isConstraint() Returns true if this expression is tagged as constraint in the model, false otherwise.
boolean	isDecision() Returns true if this expression is typed as decision in the model, false otherwise.
boolean	isDouble() Returns true if this expression is a double, false otherwise.
boolean	isInt() Returns true if this expression is an integer, false otherwise.
boolean	isNamed() Returns true if this expression has a name, and false otherwise.
boolean	isObjective() Returns true if this expression is tagged as objective in the model, false otherwise.
boolean	isViolated() Returns true if the given expression is violated in the best solution found by the solver.
void	setDoubleValue(double value) Sets the value of this expression in the current solution found by the solver.
void	setIntValue(long value) Sets the value of this expression in the current solution found by the solver.
void	setName(java.lang.String name) Sets the name of this expression.
void	setOperand(int operandIndex, double constant) Replaces the operand of the given index.
void	setOperand(int operandIndex, long constant) Replaces the operand of the given index.
void	setOperand(int operandIndex, LSExpression operand) Replaces the operand of the given index.
void	setValue(double value) Sets the value of this expression in the current solution found by the solver.
void	setValue(long value) Sets the value of this expression in the current solution found by the solver.
java.lang.String	toString()

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Method Detail

getModel

public LSModel getModel()

getLocalSolver

public LocalSolver getLocalSolver()

getOperator

public LSOperator getOperator()

Gets the operator of this expression.

Returns:

Operator.

getIndex

public int getIndex()

Gets the index of this expression in the model.

Returns:

Index in the model.

isConstant

public boolean isConstant()

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

Returns:

True if typed as constant.

isDecision

public boolean isDecision()

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

Returns:

True if typed as decision.

isConstraint

public boolean isConstraint()

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

Returns:

True if tagged as constraint.

isObjective

public boolean isObjective()

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

Returns:

True if tagged as objective.

isDouble

public boolean isDouble()

Returns true if this expression is a double, false otherwise. Only allowed in states LSState.Paused or LSState.Stopped.

Returns:

True if the expression is a double.

Since:

3.0

isInt

public boolean isInt()

Returns true if this expression is an integer, false otherwise. Only allowed in states LSState.Paused or LSState.Stopped. Note that a boolean is also an integer.

Returns:

True if the expression is a double.

Since:

3.0

isBool

public boolean isBool()

Returns true if this expression is a boolean (ie 0 or 1), false otherwise. Only allowed in states LSState.Paused or LSState.Stopped.

Returns:

True if the expression is a boolean.

Since:

3.0

isArray

public boolean isArray()

Returns true if this expression is an array, false otherwise. Only allowed in states LSState.Paused or LSState.Stopped.

Returns:

True if the expression is an array.

Since:

3.1

isCollection

public boolean isCollection()

Returns true if this expression is a collection, false otherwise. Only allowed in states LSState.Paused or LSState.Stopped.

Returns:

True if the expression is a collection.

Since:

5.5

addOperand

public void addOperand(LSExpression expr)

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

Parameters:

expr - Operand to add.

addOperand

public void addOperand(long constant)

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

Parameters:

constant - Constant operand to add.

addOperand

public void addOperand(double constant)

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

Parameters:

constant - Constant operand to add.

addOperands

public void addOperands(java.lang.Iterable<LSExpression> operands)

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

Parameters:

operands - The iterable collection of operands to be added.

Since:

5.5

addOperands

public void addOperands(long... operands)

Add the given constant integer operands to this expression. Only allowed in state LSState.Modeling.

Parameters:

operands - The constant integer operands to be added.

Since:

5.5

addOperands

public void addOperands(double... operands)

Add the given constant double operands to this expression. Only allowed in state LSState.Modeling.

Parameters:

operands - The constant double operands to be added.

Since:

5.5

addOperands

public void addOperands(LSExpression... operands)

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

Parameters:

operands - The operands to be added.

Since:

5.5

getOperand

public LSExpression getOperand(int operandIndex)

Gets the operand with the given index.

Parameters:

operandIndex - Index of the operand.

Returns:

Operand.

setOperand

public void setOperand(int operandIndex,
              LSExpression operand)

Replaces the operand of the given index.

Parameters:

operandIndex - Index of the operand to change

operand - New operand

setOperand

public void setOperand(int operandIndex,
              long constant)

Replaces the operand of the given index.

Parameters:

operandIndex - Index of the operand to change.

constant - New constant operand.

setOperand

public void setOperand(int operandIndex,
              double constant)

Replaces the operand of the given index.

Parameters:

operandIndex - Index of the operand to change.

constant - New constant operand.

Since:

3.0

getNbOperands

public int getNbOperands()

Gets the number of operands of this expression.

Returns:

Number of operands.

setValue

public void setValue(long value)

Sets the value of this expression in the current solution found by the solver. Only allowed for decisions. Only allowed in state LSState.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(LSExpression, long) and has the same behavior as setIntValue(long).

Parameters:

value - Value assigned to this expression.

See Also:

LSSolution.setValue(LSExpression, long), isInt(), isBool()

setValue

public void setValue(double value)

Sets the value of this expression in the current solution found by the solver. Only allowed for decisions. Only allowed in state LSState#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(LSExpression, double) and has the same behavior as setDoubleValue(double).

Parameters:

value - Value assigned to this expression.

See Also:

LSSolution.setValue(LSExpression expr, double value), isDouble()

setIntValue

public void setIntValue(long value)

Sets the value of this expression in the current solution found by the solver. Only allowed for decisions. Only allowed in state LSState.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(LSExpression, long).

Parameters:

value - Value assigned to this expression.

Since:

3.0

See Also:

LSSolution.setIntValue(LSExpression, long), isInt(), isBool()

setDoubleValue

public void setDoubleValue(double value)

Sets the value of this expression in the current solution found by the solver. Only allowed for decisions. Only allowed in state LSState.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(LSExpression, double).

Parameters:

value - Value assigned to this expression.

Since:

3.0

See Also:

LSSolution.setDoubleValue(LSExpression, double), isDouble()

getValue

public long getValue()

Gets the value of this expression in the best solution found by the solver. Only allowed in states LSState.Paused or LSState.Stopped. Only allowed if this expression is an integer or a boolean. This method is a shortcut for LSSolution.getValue(LSExpression).

Returns:

Value in the best solution.

See Also:

LSSolution.getValue(LSExpression), isInt(), isBool()

getIntValue

public long getIntValue()

Gets the value of this expression in the best solution found by the solver. Only allowed in states LSState.Paused or LSState.Stopped. Only allowed if this expression is an integer or a boolean. This method is a shortcut for LSSolution.getIntValue(LSExpression).

Returns:

Value in the best solution.

Since:

3.0

See Also:

LSSolution.getIntValue(LSExpression), isInt(), isBool()

getDoubleValue

public double getDoubleValue()

Gets the value of this expression in the best solution found by the solver. Only allowed in states LSState.Paused or LSState.Stopped. Only allowed if this expression is a double. This method is a shortcut for LSSolution.getDoubleValue(LSExpression).

Returns:

Value in the best solution.

Since:

3.0

See Also:

LSSolution.getDoubleValue(LSExpression), isDouble()

getCollectionValue

public LSCollection getCollectionValue()

Gets the value of this expression in the best solution found by the solver. Only allowed in states LSState.Paused or LSState.Stopped. Only allowed if this expression is a collection (list). This method is a shortcut for LSSolution.getCollectionValue(LSExpression).

Returns:

Value in the best solution.

Since:

5.5

See Also:

LSSolution.getCollectionValue(LSExpression)

isViolated

public boolean isViolated()

Returns true if the given expression is violated in the best solution found by the solver. An expression can be violated in 3 cases: 1. it is a constraint and its value is 0 2. it is a a double and its value is NaN (NotANumber) 3. it is an integer or boolean with no valid value (arithmetic or out of bounds exception). Only allowed in states LSState.Paused or LSState.Stopped. This method is a shortcut for LSSolution.isViolated(LSExpression).

Returns:

True if this expression is violated in the best solution.

Since:

5.5

setName

public void setName(java.lang.String name)

Sets the name of this expression. Only allowed in state LSState.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.

isNamed

public boolean isNamed()

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

Returns:

True if named.

getName

public java.lang.String getName()

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

Returns:

Name.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getInfo

public java.lang.String getInfo()

Returns useful info about this expression (according to the state of LocalSolver). Useful for debugging or logging purposes.

Returns:

Info about this search during the solving process.

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object