This topic contains the following sections:
BMC TrueSight Capacity Optimization enables you to create your own formulas to use in different analyses, and in quick analyses.
Using the Formula editor, you can create your own formulas that are derived from metrics associated with BMC TrueSIght Capacity Optimization entity types. These custom formulas compute values based on selected metrics from the selected entity types.
With custom formulas, you can:
To access the Formulas page in the BMC TrueSight Capacity Optimization console, click Administration > DATA WAREHOUSE > Formulas. The Formulas page allows you to view the existing formulas, and define new ones.
Formulas are derived from metrics. While they share a lot of similarities, they differ in a few ways. The following table lists the similarities and differences:
Characteristic  Formulas  Metrics 

Can be used:
 
Analysis functions allowed:
Warning If you choose aggregation in the analysis editor while using a formula, then formulas and aggregation interact in a way that is not intuitive. Aggregation options are applied first on the underlying metrics, and then the formula is evaluated against the aggregated metrics. The results may not be as expected.  
Analysis function 'Correlation'  
Can be used in Resource Monitor Rules  
Can be used in Hierarchy Rules  
Stored in data warehouse^{1}  
Forecasted values and Statistic selection^{2}  
Available in PV tables 
^{1} Formulas are dynamically computed based on the input metrics, and hence their values are not stored in the data warehouse.
^{2} Statistic selection is applicable only when you store data in the data warehouse. For formulas, since the data is not stored, and the computation is carried out dynamically when it extracts the input metrics and then does the charting, Forecasted values and Statistic selection are not possible for formulas.
For each formula, the Administration > DATA WAREHOUSE > Formulas page displays information about each formula. There are two types of formulas listed, builtin and custom. The information is displayed in the following columns:
Column  Description 

Formula Name  Internal name of the formula generated by the system using the userdefined name. All custom formula names have a _C suffix. 
Formula Label  Userdefined name that is used as the label in charts and reports. 
Package  Denotes if the formula is inbuilt or custom. 
Edit formula  Click to edit a formula. You can edit only custom formulas. 
Delete formula  Click to delete a formula. Note

To add a new formula, do the following:
Navigate to Administration > DATA WAREHOUSE > Formulas.
Click Add new formula.
The Add a new formula page is displayed.
Specify the following details in the Add a new formula page:
Field  Description 

Metric Selection  
Target Entity Category  Select a target entity category for the formula from the following options:

Target Entity Type  From the selected target entity category, narrow down to the target entity type to associate the formula with. BMC TrueSight Capacity Optimization uses this entity type to filter the list of metrics to select from.
If you do not select a Target Entity, the formula is associated with all entity types. 
Input Metrics for Target Entity Type  Available only in the Advanced mode. Select which metrics to display for the target entity type that you selected in the earlier step:

Input Metrics from Target Entity  Select an input metric from the list, based on the Target Entity Type.

Additional input metrics  Available only in the Advanced mode. Select additional metrics to associate to the formula:

Formula  
Formula  Build the formula.This section consists of the Formula Builder box, Operators, Functions, Target Input Metrics and Parent Input Metrics. All metric names added to the Target Input Metrics or Parent Input Metrics list start with "Target." or "Parent." respectively. To write the formula, do the following:

Formula Label  Type legend text for the formula that will be displayed on the chart. 
Formula Name  The formula name is automatically generated using the Formula Label. It starts with "F_" and ends with the "_C" suffix. If a space is used in the Formula Label, it is converted to underscore (_). 
Formula Result Type  Select a result type for the formula. This result type is used to compute the formula value. 
Select unit  Assign a unit of measure to the formula from the following options:
On save, the custom unit created is displayed in existing list. The selected unit is represented on the yaxis of the chart. 
Using a custom formula in an analysis