org.cloudsimplus.heuristics

Class CloudletToVmMappingSolution

java.lang.Object

org.cloudsimplus.heuristics.CloudletToVmMappingSolution

All Implemented Interfaces:

Comparable<HeuristicSolution<Map<Cloudlet,Vm>>>, HeuristicSolution<Map<Cloudlet,Vm>>

public class CloudletToVmMappingSolution
extends Object
implements HeuristicSolution<Map<Cloudlet,Vm>>

A possible solution for mapping a set of Cloudlets to a set of Vm's. It represents a solution generated using a Heuristic implementation.

Since:

CloudSim Plus 1.0

Author:

Manoel Campos da Silva Filho

See Also:

Heuristic

Field Summary

Fields

Modifier and Type	Field and Description
static double	MIN_DIFF When two double values are subtracted to check if they are equal zero, there may be some precision issues.

Fields inherited from interface org.cloudsimplus.heuristics.HeuristicSolution

LOGGER, NULL

Constructor Summary

Constructors

Constructor and Description
CloudletToVmMappingSolution(CloudletToVmMappingSolution solution) Clones a given solution.
CloudletToVmMappingSolution(Heuristic heuristic) Creates a new solution for mapping a set of cloudlets to VMs using a given heuristic implementation.

Method Summary

Modifier and Type	Method and Description
void	bindCloudletToVm(Cloudlet cloudlet, Vm vm) Binds a cloudlet to be executed by a given Vm.
int	compareTo(HeuristicSolution solution) Compares this solution with another given one, based on the solution cost.
double	getCost() Defines the cost of using this solution.
double	getCost(boolean forceRecompute) It computes the costs of the entire mapping between Vm's and cloudlets.
Heuristic<HeuristicSolution<Map<Cloudlet,Vm>>>	getHeuristic()
protected List<Map.Entry<Cloudlet,Vm>>	getRandomMapEntries() Try to get 2 randomly selected entries from the cloudletVmMap.
Map<Cloudlet,Vm>	getResult() Gets the result of the solution.
double	getVmCost(Map.Entry<Vm,List<Map.Entry<Cloudlet,Vm>>> entry) Computes the cost of all Cloudlets hosted by a given Vm.
double	getVmCost(Vm vm, List<Cloudlet> cloudlets) Computes the cost of all Cloudlets hosted by a given Vm.
protected boolean	swapVmsOfTwoMapEntries(List<Map.Entry<Cloudlet,Vm>> entries) Swap the Vm's of 2 randomly selected cloudlets in the cloudletVmMap in order to provide a neighbor solution.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.cloudsimplus.heuristics.HeuristicSolution

getFitness

Field Detail

MIN_DIFF

public static final double MIN_DIFF

When two double values are subtracted to check if they are equal zero, there may be some precision issues. This value is used to check the absolute difference between the two values to avoid that solutions with little decimal difference be considered different one of the other.

See Also:

Constant Field Values

Constructor Detail

CloudletToVmMappingSolution

public CloudletToVmMappingSolution(Heuristic heuristic)

Creates a new solution for mapping a set of cloudlets to VMs using a given heuristic implementation.

Parameters:

heuristic - the heuristic implementation used to find the solution being created.

CloudletToVmMappingSolution

public CloudletToVmMappingSolution(CloudletToVmMappingSolution solution)

Clones a given solution.

Parameters:

solution - the solution to be cloned

Method Detail

bindCloudletToVm

public void bindCloudletToVm(Cloudlet cloudlet,
                             Vm vm)

Binds a cloudlet to be executed by a given Vm.

Parameters:

cloudlet - the cloudlet to be added to a Vm

vm - the Vm to assign a cloudlet to

getHeuristic

public Heuristic<HeuristicSolution<Map<Cloudlet,Vm>>> getHeuristic()

Specified by:

getHeuristic in interface HeuristicSolution<Map<Cloudlet,Vm>>

Returns:

the heuristic that generated this solution.

getCost

public double getCost()

Defines the cost of using this solution. As higher is the cost, worse is a solution. How a solution cost is computed is totally dependent of the heuristic implementation being used to find a solution. It computes the cost of the entire mapping between Vm's and Cloudlets.

Specified by:

getCost in interface HeuristicSolution<Map<Cloudlet,Vm>>

Returns:

the solution cost

See Also:

HeuristicSolution.getFitness()

getCost

public double getCost(boolean forceRecompute)

It computes the costs of the entire mapping between Vm's and cloudlets.

Parameters:

forceRecompute - indicate if the cost has to be recomputed anyway

Returns:

the cost of the entire mapping between Vm's and cloudlets

See Also:

getCost()

getVmCost

public double getVmCost(Map.Entry<Vm,List<Map.Entry<Cloudlet,Vm>>> entry)

Computes the cost of all Cloudlets hosted by a given Vm. The cost is based on the number of PEs from the VM that will be idle or overloaded.

Parameters:

entry - a Map Entry where the key is a VM hosting some Cloudlets and the value is the Cloudlets hosted in this VM.

Returns:

the VM cost to host the Cloudlets

getVmCost

public double getVmCost(Vm vm,
                        List<Cloudlet> cloudlets)

Computes the cost of all Cloudlets hosted by a given Vm. The cost is based on the number of PEs from the VM that will be idle or overloaded.

Parameters:

vm - the VM to compute the cost to host some Cloudlets

cloudlets - the list of Cloudlets to be hosted by the VM in order to compute the cost

Returns:

the VM cost to host the Cloudlets

compareTo

public int compareTo(HeuristicSolution solution)

Compares this solution with another given one, based on the solution cost. The current object is considered to be: equal to the given object if they have the same cost; greater than the given object if it has a lower cost; lower than the given object if it has a higher cost;

Specified by:

compareTo in interface Comparable<HeuristicSolution<Map<Cloudlet,Vm>>>

Parameters:

solution - the solution to compare this instance to

Returns:

getResult

public Map<Cloudlet,Vm> getResult()

Description copied from interface: HeuristicSolution

Gets the result of the solution. For instance, if a implementation of this interface aims to provide a mapping between Cloudlets and Vm's, this type would be a Map<Cloudlet, Vm>, that will indicate which Vm will run each Cloudlet. This way, the type T of the solution is totally dependent of the problem being solved by the heuristic implementation.

The result of solution is generated by a heuristic. Getting an optimal or sub-optimal solution is the final goal of a heuristic.

Specified by:

getResult in interface HeuristicSolution<Map<Cloudlet,Vm>>

Returns:

the actual solution, providing the mapping between Cloudlets and Vm's.

swapVmsOfTwoMapEntries

protected final boolean swapVmsOfTwoMapEntries(List<Map.Entry<Cloudlet,Vm>> entries)

Swap the Vm's of 2 randomly selected cloudlets in the cloudletVmMap in order to provide a neighbor solution. The method change the given Map entries, moving the cloudlet of the first entry to the Vm of the second entry and vice-versa.

Parameters:

entries - a List of 2 entries containing Cloudlets to swap their VMs. If the entries don't have 2 elements, the method will return without performing any change in the entries.

Returns:

true if the VMs of the Cloudlets where swapped, false otherwise

getRandomMapEntries

protected List<Map.Entry<Cloudlet,Vm>> getRandomMapEntries()

Try to get 2 randomly selected entries from the cloudletVmMap.

Returns:

a List with 2 entries from the cloudletVmMap if the map size is at least 2; an unitary List if the map has only 1 entry; or an empty List if there is no entry in the map.

See Also:

swapVmsOfTwoMapEntries(List)