StatsActor

The StatsActor (statistics actor) is a Coral Actor that gathers a single real valued field from its trigger JSON. It saves a number of statistics as state for this field.

Creating a StatsActor

The StatsActor has "type": "stats". The params value is a JSON with a single field:

field	type	required	description
`field`	string	yes	the name of the field in the trigger-JSON to collect statistics for.

Example

{
  "data": {
    "type": "actors",
    "attributes": {
      "type": "stats",
      "params": {
        "field": "amount"
      }
    }
  }
}

This will create a statistics component monitoring the field “amount”.

Trigger

The StatsActor only does useful work if the trigger is connected. The actor gathers values supplied by the field specified in the parameters.

Emit

The StatsActor emits nothing. The state of the actor should be gathered by another actor through a collect procedure.

State

The StatsActor keeps the following summary statistics as state:

field	type	description
`count`	integer	number of values processed
`avg`	float	the average value
`sd`	float	the (population) standard deviation
`min`	float	the minimum value
`max`	float	the maximum value

The state is updated every time a value for the specified field is encountered in the trigger. Note that when no events have occurred the count is zero, and other fields are undefined. This is represented as null in the JSON representation of the state.

Collect

The StatsActor does not collect state from other actors.

Timer

The StatsActor does not provide timer actions.