OptimizationProblem

java.lang.Object
- java.util.AbstractCollection<E>
- - java.util.AbstractSet<E>
  - - java.util.HashSet<Statement>
    - - net.sf.tweety.math.opt.ConstraintSatisfactionProblem
      - net.sf.tweety.math.opt.OptimizationProblem

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.lang.Iterable<Statement>, java.util.Collection<Statement>, java.util.Set<Statement>
```
public class OptimizationProblem
extends ConstraintSatisfactionProblem
```
This class models a general optimization problem.

Author:

Matthias Thimm

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`static double`	`EPSILON` Some value to represent a very small number
`static int`	`MAXIMIZE` Static constant for the type "maximization"
`static int`	`MINIMIZE` Static constant for the type "minimization"
`private int`	`penalty` penalty for converted absolute values.
`private static long`	`serialVersionUID` For serialization.
`private static int`	`STANDARD_PENALTY` standard penalty for converted minimums.
`private Term`	`targetFunction` The target function of this problem.
`private int`	`type` The type of the optimization problem.

Constructor Summary

Constructors
Constructor and Description
`OptimizationProblem()` Creates an empty optimization problem.
`OptimizationProblem(int type)` Creates an empty optimization problem of the given type.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`OptimizationProblem`	`clone()`
`void`	`collapseAssociativeOperations()` This method collapses all associative operations appearing in the target function and the constraints, e.g.
`java.lang.String`	`convertToCplexLpFormat()` Converts the this optimization problem into a string in the commonly used CPLEX LP-format for mixed integer linear programming.
`java.lang.String`	`convertToLpFormat()` Converts the this optimization problem into a string in the commonly used LP-format for mixed integer linear programming.
`java.util.Set<Minimum>`	`getMinimums()` Returns all minimums appearing in this problem.
`Term`	`getTargetFunction()` Returns the target function of this problem.
`int`	`getType()` Returns the type of this problem.
`java.util.Set<Variable>`	`getVariables()` Returns all variables of this problem.
`boolean`	`isLinear()` Checks whether every constraint of this problem is linear.
`boolean`	`isMinimumFree()` Checks whether this problem uses no minimum function.
`boolean`	`isTargetLinear()` Checks whether the target function is linear.
`void`	`resolveAbsoluteValues()` Resolves all occurrences of absolute values "abs(X)" by replacing "abs(X)" by a new variable "TMPABS" adding constraints "TMPABS - X>= 0" and "TMPABS + X >= 0" (yielding "TMPABS <= abs(X)") introducing a new variable "TMPABSB" adding constraints "X+PENALTYTMPABSB - TMPABS >= 0" and "-X-TMPABSBPENALTY - TMPABS >= -PENALTY" (yielding "TMPABS >= abs(X)") adding constraints "TMPABSB<=1"
`void`	`resolveMaximums()` Resolves all occurrences of maximums by substituting a maximum "max{a,b}" by "0.5 a + 0.5 b + abs(a-b)".
`void`	`resolveMinimums()` Resolves all occurrences of minimums by substituting a minimum "min{a,b}" by "0.5 a + 0.5 b - abs(a-b)".
`void`	`setPenalty(int penalty)` Sets the penalty for violated minimum.
`void`	`setTargetFunction(Term targetFunction)` Sets the target function of this problem.
`void`	`setType(int type)` Sets the type of this problem, either OptimizationProblem.MINIMIZE or OptimizationProblem.MAXIMIZE.
`java.lang.String`	`toString()`

Methods inherited from class net.sf.tweety.math.opt.ConstraintSatisfactionProblem
isInteger, toNormalizedForm

Methods inherited from class java.util.HashSet
add, clear, contains, isEmpty, iterator, remove, size, spliterator

Methods inherited from class java.util.AbstractSet
equals, hashCode, removeAll

Methods inherited from class java.util.AbstractCollection
addAll, containsAll, retainAll, toArray, toArray

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Set
addAll, containsAll, equals, hashCode, removeAll, retainAll, toArray, toArray

Methods inherited from interface java.util.Collection
parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable
forEach

- Field Detail
  - serialVersionUID
```
private static final long serialVersionUID
```
    For serialization.
    
    See Also:
    
    Constant Field Values
  - EPSILON
```
public static final double EPSILON
```
    Some value to represent a very small number
    
    See Also:
    
    Constant Field Values
  - MINIMIZE
```
public static final int MINIMIZE
```
    Static constant for the type "minimization"
    
    See Also:
    
    Constant Field Values
  - MAXIMIZE
```
public static final int MAXIMIZE
```
    Static constant for the type "maximization"
    
    See Also:
    
    Constant Field Values
  - STANDARD_PENALTY
```
private static final int STANDARD_PENALTY
```
    standard penalty for converted minimums.
    
    See Also:
    
    Constant Field Values
  - penalty
```
private int penalty
```
    penalty for converted absolute values.
  - type
```
private int type
```
    The type of the optimization problem.
  - targetFunction
```
private Term targetFunction
```
    The target function of this problem.
- Constructor Detail
  - OptimizationProblem
```
public OptimizationProblem()
```
    Creates an empty optimization problem.
  - OptimizationProblem
```
public OptimizationProblem(int type)
```
    Creates an empty optimization problem of the given type.
    
    Parameters:
    
    type - the type of the problem; either OptimizationProblem.MINIMIZE or OptimizationProblem.MAXIMIZE.
- Method Detail
  - setTargetFunction
```
public void setTargetFunction(Term targetFunction)
```
    Sets the target function of this problem.
    
    Parameters:
    
    targetFunction - a term.
  - isTargetLinear
```
public boolean isTargetLinear()
```
    Checks whether the target function is linear.
    
    Returns:
    
    "true" if the target function is linear.
  - isLinear
```
public boolean isLinear()
```
    Description copied from class: ConstraintSatisfactionProblem
    
    Checks whether every constraint of this problem is linear.
    
    Overrides:
    
    isLinear in class ConstraintSatisfactionProblem
    
    Returns:
    
    "true" if every constraint of this problem is linear.
  - isMinimumFree
```
public boolean isMinimumFree()
```
    Description copied from class: ConstraintSatisfactionProblem
    
    Checks whether this problem uses no minimum function.
    
    Overrides:
    
    isMinimumFree in class ConstraintSatisfactionProblem
    
    Returns:
    
    "true" if this problem uses no minimum function.
  - resolveMinimums
```
public void resolveMinimums()
```
    Description copied from class: ConstraintSatisfactionProblem
    
    Resolves all occurrences of minimums by substituting a minimum "min{a,b}" by "0.5 a + 0.5 b - abs(a-b)".
    
    Overrides:
    
    resolveMinimums in class ConstraintSatisfactionProblem
  - resolveMaximums
```
public void resolveMaximums()
```
    Description copied from class: ConstraintSatisfactionProblem
    
    Resolves all occurrences of maximums by substituting a maximum "max{a,b}" by "0.5 a + 0.5 b + abs(a-b)".
    
    Overrides:
    
    resolveMaximums in class ConstraintSatisfactionProblem
  - resolveAbsoluteValues
```
public void resolveAbsoluteValues()
```
    Resolves all occurrences of absolute values "abs(X)" by
    - replacing "abs(X)" by a new variable "TMPABS"
    - adding constraints "TMPABS - X>= 0" and "TMPABS + X >= 0" (yielding "TMPABS <= abs(X)")
    - introducing a new variable "TMPABSB"
    - adding constraints "X+PENALTY*TMPABSB - TMPABS >= 0" and "-X-TMPABSB*PENALTY - TMPABS >= -PENALTY" (yielding "TMPABS >= abs(X)")
    - adding constraints "TMPABSB<=1"
  - convertToLpFormat
```
public java.lang.String convertToLpFormat()
```
    Converts the this optimization problem into a string in the commonly used LP-format for mixed integer linear programming.
    
    Returns:
    
    A string representing this problem in LP-format
  - convertToCplexLpFormat
```
public java.lang.String convertToCplexLpFormat()
```
    Converts the this optimization problem into a string in the commonly used CPLEX LP-format for mixed integer linear programming.
    
    Returns:
    
    A string representing this problem in CPLEX LP-format
  - getVariables
```
public java.util.Set<Variable> getVariables()
```
    Description copied from class: ConstraintSatisfactionProblem
    
    Returns all variables of this problem.
    
    Overrides:
    
    getVariables in class ConstraintSatisfactionProblem
    
    Returns:
    
    all variables of this problem.
  - getMinimums
```
public java.util.Set<Minimum> getMinimums()
```
    Description copied from class: ConstraintSatisfactionProblem
    
    Returns all minimums appearing in this problem.
    
    Overrides:
    
    getMinimums in class ConstraintSatisfactionProblem
    
    Returns:
    
    all minimums appearing in this problem.
  - collapseAssociativeOperations
```
public void collapseAssociativeOperations()
```
    Description copied from class: ConstraintSatisfactionProblem
    
    This method collapses all associative operations appearing in the target function and the constraints, e.g. every min{min{a,b},c} becomes min{a,b,c}
    
    Overrides:
    
    collapseAssociativeOperations in class ConstraintSatisfactionProblem
  - setType
```
public void setType(int type)
```
    Sets the type of this problem, either OptimizationProblem.MINIMIZE or OptimizationProblem.MAXIMIZE.
    
    Parameters:
    
    type - the type of this problem.
  - setPenalty
```
public void setPenalty(int penalty)
```
    Sets the penalty for violated minimum.
    
    Parameters:
    
    penalty -
  - getType
```
public int getType()
```
    Returns the type of this problem.
    
    Returns:
    
    the type of this problem.
  - getTargetFunction
```
public Term getTargetFunction()
```
    Returns the target function of this problem.
    
    Returns:
    
    the target function of this problem.
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class ConstraintSatisfactionProblem
  - clone
```
public OptimizationProblem clone()
```
    Overrides:
    
    clone in class ConstraintSatisfactionProblem

Class OptimizationProblem

Field Summary

Constructor Summary

Method Summary

Methods inherited from class net.sf.tweety.math.opt.ConstraintSatisfactionProblem

Methods inherited from class java.util.HashSet

Methods inherited from class java.util.AbstractSet

Methods inherited from class java.util.AbstractCollection

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Set

Methods inherited from interface java.util.Collection

Methods inherited from interface java.lang.Iterable

Field Detail

serialVersionUID

EPSILON

MINIMIZE

MAXIMIZE

STANDARD_PENALTY

penalty

type

targetFunction

Constructor Detail

OptimizationProblem

OptimizationProblem

Method Detail

setTargetFunction

isTargetLinear

isLinear

isMinimumFree

resolveMinimums

resolveMaximums

resolveAbsoluteValues

convertToLpFormat

convertToCplexLpFormat

getVariables

getMinimums

collapseAssociativeOperations

setType

setPenalty

getType

getTargetFunction

toString

clone