Object Reference : Object View and Procedure Reference : Alpha
Declare an alpha series object with a formula for auto-updating, or specify a formula for an existing alpha series.
frml alpha_name = alpha_expression
frml alpha_name = @clear
Follow the frml keyword with a name for the alpha series, and an assignment statement. The special keyword “@CLEAR” is used to return the auto-updating series to an alpha series.
To define an auto-updating alpha series, you must use the frml keyword prior to entering an assignment statement. If FIRST_NAME and LAST_NAME are alpha series, then the formula declaration:
frml full_name = first_name + " " + last_name
creates an auto-updating alpha series FULL_NAME.
You may apply a frml to an existing alpha series. The commands:
alpha state_info
frml state_info = state_name + state_id
makes the previously created alpha series STATE_INFO an auto-updating series containing the alpha series STATE_NAME and STATE_ID. Note that once an alpha series is defined to be auto-updating, it may not be modified directly. Here, you may not edit STATE_INFO, nor may you generate data into the alpha series.
Note that the commands:
alpha state_info
state_info = state_name + state_id
while similar, produce quite different results, since the absence of the frml keyword in the second example means that EViews will generate fixed values in the alpha series instead of defining a formula to generate the alpha series values. In this latter case, the values in the alpha series STATE_INFO are fixed, and may be modified directly.
One particularly useful feature of auto-updating series is the ability to reference series in databases. The command:
frml states = usdata::states
creates an alpha series called STATES that obtains its values from the alpha series STATES in the database USDATA.
To turn off auto-updating for an alpha series, you should use the special expression “@CLEAR” in your frml assignment. The command:
frml id = @clear
sets freezes the contents of the series at the current values.
See “Auto-Updating Series”.
See also Link::link.