Resource Pool

Pool entity resources

• Library:

• SimEvents / Entity Management

  SimEvents

• 

Description

The Resource Pool block defines resources that entities can use during model simulation. Use the Resource Acquirer and Resource Releaser blocks to work with these resources.

Initialize the block with the specified amount of available resources. Then:

• Use one or more Resource Acquirer blocks to reserve those resources.

• Use a Resource Releaser block to return resources back to this block for future use.

You can determine the visibility of available resources in a model hierarchy. You can choose Global or Scoped resources in the pool.

• Global — Resources can be referenced from anywhere in a model hierarchy.

• Scoped — Resources are locally visible and can be referenced only from the subsystem that contains the Resource Pool block and all the subsystems inside.

Ports

Input

Port_1 — Change resource amount

scalar | vector | matrix

Input entity port for changing resource amount. The input cannot be a negative value.

Dependencies

To enable this port, select the Change amount through control port as the Resource amount source.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point

Output

Port_u — Outputs the number of resources that are in use

scalar

Number of resources that are in use.

Dependencies

To enable this port, click the Statistics tab and select the box labeled Amount in use, u.

Data Types: double

Port_util — Outputs the average time the pool is utilized

scalar

Average wait time the pool is utilized.

Dependencies

To enable this port, click the Statistics tab and select the box labeled Average utilization, util.

Data Types: double

Port_avail — Outputs the number of resources that are available

scalar

Number of resources that are available.

Dependencies

To enable this port, click the Statistics tab and select the box labeled Amount available, avail.

Data Types: double

Parameters

Resource name — Name for the resources in the pool

Resource1 (default) | character vector

Enter name of entity resource.

Programmatic Use

Block Parameter: ResourceName

Type: character vector

Values: 'Resource1' | character vector

Default: 'Resource1'

Resource granularity — Select granularity of resource use

Discrete unit (default) | Fractional amount

Select granularity of resource use.

• Discrete unit — Use whole number increment.

• Fractional amount — Use fractional increment.

Programmatic Use

Block Parameter: ResourceGranularity

Type: character vector

Values: 'Discrete unit' | 'Fractional amount'

Default: 'Discrete unit'

Reusable upon release — Specify if the resource is reusable upon release

off (default) | on

• Select this check box to allow this resource to return to the resource pool upon release. An example of such a resource is a table in a restaurant, which is available for reuse when a customer leaves.

• Clear this check box to prevent this resource from returning to the resource pool upon release. In this case, when the resource is released, it is no longer available in the resource pool. An example of such a resource is food in a restaurant, which is not reusable upon consumption.

Programmatic Use

Block Parameter: ReusableUponRelease

Type: character vector

Values: 'on' | 'off'

Default: 'off'

Resource amount source — Select resource amount source

Dialog (default) | Change amount through control port

Select resource amount source.

• Dialog

• Change amount through control port

  Select this option to enable an input entity port and a variable capacity resource. The payload of the arriving message increments the existing number of resources for the block. For example, if the resource pool has five resources, and a message with a payload of three arrives at the input port, the block has eight resources available. The number of resources cannot decrement.

Programmatic Use

Block Parameter: ResourceAmountSource

Type: character vector

Values: 'Dialog' | 'Change amount through control port'

Default: 'Dialog'

Resource amount — Set the amount of resource

10 (default) | scalar

Enter amount of resource.

Dependencies

Select the Dialog to enable the Resource amount source.

Programmatic Use

Block Parameter: ResourceAmount

Type: character vector

Values: '10' | scalar

Default: '10'

Initial resource amount — Enter initial amount of resource

10 (default) | scalar

Enter initial amount of resource.

Dependencies

Select the Change amount through control port to enable the Resource amount source.

Programmatic Use

Block Parameter: InitialResourceAmount

Type: character vector

Values: '10' | scalar

Default: '10'

Resource visibility — Select the availability of the resources

Global (default) | Scoped

Choose the behavior of the resources acquired from this pool as Global or Scoped.

When Global is selected:

• Resource pool names must be unique in the model.

• All resources have global scope and they can be referenced from anywhere in a model hierarchy.

• An entity carrying a resource acquired from this block, must explicitly relinquish the resource.

• When an entity is destroyed, the resources that are associated with it are returned to the pool, if the Reusable upon release check box is selected.

When Scoped is selected:

• Resources are locally visible and can be referenced only from the subsystem that contains the Resource Pool block and all the subsystems inside.

• Resource pool names must be unique within the model hierarchy where the Resource Pool block is visible.

• An entity carrying the resource acquired from this block, must explicitly relinquish the resource.

• When an entity leaves the scope, any resources that are local to that scope and not already released, are automatically released. If Reusable upon release check box is selected, they are returned to the pool.

Programmatic Use

Block Parameter: InitialResourceAmount

Type: character vector

Values: '10' | scalar

Default: '10'

Amount in use, u — Number of resources that are in use

off (default) | on

Outputs the amount of resources that the block has acquired and has not yet released. For example, if the resource pool has 10 resources, and the entity acquires all of them, this port shows 10. When the block releases the resources, this port shows 0.

Programmatic Use

Block Parameter: AmountInUse

Type: character vector

Values: 'on' | 'off'

Default: 'off'

Average utilization, util — Outputs the average resource utilization

off (default) | on

Outputs the average resource utilization.

Programmatic Use

Block Parameter: AverageUtilization

Type: character vector

Values: 'on' | 'off'

Default: 'off'

Amount available, avail — Outputs the amount of resources available

off (default) | on

Outputs the amount of resources available.

Programmatic Use

Block Parameter: AmountAvailable

Type: character vector

Values: 'on' | 'off'

Default: 'off'

Model Examples

Using Custom Visualization for Entities

These examples show how you can create MATLAB based custom visualization for entities. The example illustrates the visualization of a restaurant layout with customer entities entering, dining, and leaving.

Resource Allocation from Multiple Pools

A technique for allocating resources from multiple resource pools. It shows how to choose a pool from which to draw a resource, based on given criteria.

Optimization of Shared Resources in a Batch Production Process

Model and optimize the use of shared resources in a system, to identify resource deficiencies and improve capacity planning. The example is based on a batch production process, where production orders are processed only according to the availability of batch reactors. In the example, SimEvents® entities represent both the production orders of the manufacturing process, and the batch reactors that are required to process them. Later in the example, we will find the optimal resource capacities of the system by applying the Genetic Algorithm solver of MATLAB Global Optimization Toolbox.