Simulation preferences
At the highest level of application are the simulation preferences. Values for these attributes are set through the preferences window, and are used as default values for new simulation snapshots and profiles.
Simulation preferences can be set at any time, and all simulation snapshots that you create after you update the preferences will inherit those preferences. |
Simulation snapshot settings
At the next level of specificity are the simulation snapshot settings. The simulation snapshot settings present a subset of the attributes available in the preferences. The initial values for these attributes are taken from the preferences. However, you can override these values by editing the "snapshot defaults".
Simulation snapshot settings will override preferences. A simulation snapshot is a record of a modeling project at the single moment when the snapshot is created. When you create a simulation snapshot, simulation default values are created as part of the snapshot. When you update the default settings (located in the Defaults folder of the snapshot), all simulation profiles that you subsequently create will inherit those new attributes. |
Simulation profile
More specific than the simulation snapshot settings are values inside a particular simulation profile. These settings, take their initial values from a combination of the simulation preferences and simulation snapshot settings. When you run a simulation or carry out an analysis on a simulation profile, it is the simulation profile settings that are used. Overriding the values of a specific profile affect the details of simulations you run against the profile, which will be reflected in any dynamic analyses you run against those results.
Process and task settings are specific to a single simulation profile, and will override both preferences and snapshot settings. You can update process and task settings of an individual simulation profile using the Attributes View. |
Setting simulation attributes for activities
You can set values for the simulation attributes of specific activity elements in the simulation diagram. These values can override inherited defaults and values or define new conditions and behaviors for individual activities within a process.
Most activity attributes that are used in simulation, such as costs, durations, and resource requirements, can be specified in the original process model. When you create a new simulation profile, the original attribute values from the process model are used in the simulation profile. If a value is not set in the process model, then the simulation profile takes the value set by the simulation snapshot settings (the Defaults folder within the simulation snapshot).
You can customize a simulation profile by overriding any of the simulation attribute values inherited from the process model or from the local preferences. |
Setting simulation preferences
The simulation preferences define the values used to populate newly created simulation snapshots.
Simulation preferences provide default values to all new simulation snapshots, and their initial simulation profiles. Subsequent simulation profiles, however, take their default settings from the snapshot settings instead of referring back to the preferences. In addition, the simulation preferences are used to determine which database will be used to hold the simulation results.
Simulation preferences are applied across all modeling projects in your workspace. When you create a new simulation snapshot by simulating an existing process model, the values of the local simulation preferences are derived from the preferences that you have set.
You can update the following simulation preferences settings: 
- Setting the database connection preferences
Derby is provided as the default database to store simulation results, but you can also set the preferences to use a locally installed copy of IBM® DB2 Universal Database™ Express Edition if you require higher performance during simulation and analysis.
- Specifying general simulation preferences
General simulation preferences define conditions and behaviors for a process as a whole during a simulation. Attributes that you set in the simulation preferences provide default values for simulation snapshots, and their initial profiles.
- Setting the simulation profile label preferences
Set the simulation labelling preferences to create a set of default display behaviors for new simulation profiles. These preferences dictate whether labels are initially displayed in simulation profiles, and specify the content that is displayed in each label. For example, you can choose to display the associated data for repositories, and the organizations and locations for tasks.
- Choosing the label display behavior for new simulation profiles
You can choose one of two sets of label preferences to use when you create new simulation profiles. You can either choose to reuse the labelling preferences that you defined for display of the process models as you edit them, or you can use your own specific simulation diagram label preferences. You can change the preferences that you are using as your default in the Simulation preferences window.
- Setting diagram display preferences
WebSphere Business Modeler allows you to display your simulation profile diagrams using enhanced graphics, or basic graphics.
- Setting task simulation preferences (General tasks
, Cost and Revenue task )
Task simulation attributes define conditions and behaviors for individual activities within a process during a simulation. Use the task simulation preferences to define default values for these attributes so that they are applied to all new simulation snapshots that you create.
- Specifying token creation preferences
You can specify preferences for token creation settings to apply to the inputs of all new simulation snapshots you create.
- Setting layout preferences
You can specify the amount of space that the Auto-Layout option will leave between nodes in the process diagram and the simulation diagram.
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Specifying simulation snapshot settings
The simulation snapshot settings provide default values for new simulation profiles created from that snapshot. The snapshot's own initial values, and the values of the initial profile included in the snapshot, are derived from the simulation preferences. If you make a change to the simulation snapshot settings, any profiles already created from that snapshot remain unaffected.
- Specifying general simulation snapshot settings (
)
General simulation snapshot settings define default conditions and behaviors for the attributes that affect the simulation profile as a whole.
- Specifying simulation snapshot settings for token creation (
)
You can specify token creation settings that apply to all new simulation profiles you create with a particular simulation snapshot. When you add token creation settings to the inputs of a simulated process or an activity within a simulated process, these settings are used as the default values.
- Specifying task simulation snapshot settings(General
, Cost and Revenue )
Task simulation settings define conditions and behaviors for individual activities within a process during a simulation. This settings are applied as defaults to all new simulation profiles that you create within a simulation snapshot.
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Specifying simulation profile settings
The attribute values that you set in the simulation profile are the values that are used when you carry out analysis on the profile or when you run a simulation.
Use these attributes to override any default values that have been inherited from the simulation snapshot settings or the simulation preferences. Modify the attributes of the top-level process to influence how the simulation runs as a while. Modify the attributes for specific activities to fine-tune the simulation to better reflect the real-world situation it models.
- Specifying label display settings for a simulation profile
The label display settings determine which labels, if any, are displayed in simulation profiles, and specify the content that is displayed in each label. For example, you can choose to display the associated data for repositories, and the organizations and locations for tasks.
- Specifying token creation settings
You can specify settings for inputs of a simulated process or an activity within the process that determine the rate, quantity, start time, and cost of these inputs.
- Specifying general process simulation settings in a simulation profile
The general simulation settings for a top level process define many of the parameters used when you run a simulation on the profile. Attributes included under this heading include the start and end times of the process simulation, the maximum number of tokens to process, and a seed for the random number generator.
- Specifying input logic settings
For processes and for activities within a process, you can specify probabilities that a set of inputs will result in a particular set of outputs correlated to the input set. For top level processes, you can also specify a probability that the inputs used to start the process will match the inputs defined by each input criterion.
- Specifying business item creation rules
For an activity within a process, you can specify rules that govern how values are assigned to business items that will be used in the simulation.
- Setting resource availability
You can specify the resources that will be made available to a process during a process simulation.
- Setting interrupts
You can set interrupts on a process or an activity within a simulation profile. Interrupts define conditions that cause the process simulation to pause if the condition occurs during a simulation run.
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Note: To change the simulation attributes for internal elements of loops and subprocesses, click the Expand all  icon on the main toolbar. The Simulation view displays the contents of all loops and subprocesses. You can then select elements within the expanded loop or subprocess and edit their simulation attributes.
- Specifying activity attributes in table format
You can quickly view and update the majority of activity-level simulation attributes for a simulation profile by using the simulation attributes table.
- Specifying token creation settings
You can specify settings for inputs of a simulated process or an activity within the process that determine the rate, quantity, start time, and cost of these inputs.
- Specifying maximum number of simultaneous tasks
For activities in a process simulation, you can specify the maximum number of instances of the activity that can exist simultaneously. When the simulation runs, it can invoke as many instances of the activity as it requires to process incoming flows simultaneously, up to the maximum number that you specify.
- Specifying processing time
For activities in a process simulation, you can specify the processing time. This is the time while the activity is actively executing, rather than the elapsed time, which may include delays while waiting for a resource. The value you specify can be a constant value, or it can be derived according to a distribution that you specify.
- Specifying resource wait times
For activities in a process simulation, you can specify the maximum time that the activity will wait for a resource before the activity fails.
- Specifying task processing cost
For activities in a process simulation, you can specify a cost incurred each time the activity runs.
- Specifying startup costs for tasks
For activities in a process simulation, you can specify a cost that will be incurred the first time the activity is used in the simulation. For each activity, only the first instance incurs this cost.
- Specifying idle cost
For activities in a process simulation, you can specify a cost rate for time they spend idle because they are waiting for a resource.
- Specifying task revenue
For activities in a process simulation, you can specify the revenue that will be generated by completing the activity.
- Specifying input logic settings
For processes and for activities within a process, you can specify probabilities that a set of inputs will result in a particular set of outputs correlated to the input set. For top level processes, you can also specify a probability that the inputs used to start the process will match the inputs defined by each input criterion.
- Specifying output logic settings
For subprocesses and for activities within a process, you can specify logic that determines what combination of outputs the activity produces in a simulation run from all possible outputs defined in the output criteria.
- Specifying loop probabilities
For while loops and do-while loops within a simulation profile, you can specify a probability that the loop condition will be satisfied and that the sequence of activities defined within the loop will be completed. The probability is applied to each repetition of the loop.
- Specifying business item creation rules
For an activity within a process, you can specify rules that govern how values are assigned to business items that will be used in the simulation.
- Setting interrupts
You can set interrupts on a process or an activity within a simulation profile. Interrupts define conditions that cause the process simulation to pause if the condition occurs during a simulation run.
- Specifying role requirements in a simulation profile
You can specify the roles that are required to complete an activity in a simulated process. The requirements you specify can be additional to the ones in the process model on which the simulation profile is based, or they can override the requirements specified in the process model.
- Specifying resource requirements in a simulation profile
You can edit the resources that are required to complete an activity in a simulated process. The requirements that you set can be additional to the ones specified in the process model on which the simulation profile is based, or they can override the requirements specified in the process model.
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