Histogram to Summarize Multiple Signals

[Lindsey.Wilcox]

Background

As a starting point, I have a signal that indicates the process error code (Error) and 2 signals that indicate the current container (Container 1 and Container 2).

I would like to create a histogram that summarizes which containers have the most frequent errors.  More specifically, I want to know:

• For the Container 1 signal, what is the distribution of container values when the error code is equal to 44 and 47
• For the Container 2 signal, what is the distribution of the container values when the error code is equal to 45

I want the results summarized as a single histogram.  The following steps describe how this can be achieved using conditions and capsule properties.

Solution

1. Create a condition with a capsule for each value change in the Error signal.  This can be accomplished in Formula using the following syntax

$errorSignal.toCondition()

Note: the .toCondition() operator assigns a Value property to each capsule that indicates the value of the Error signal during the capsule.  This property can be used for aggregation in a Histogram.

2.  Filter the condition created in Step 1 to only include capsules with errors of interest for the Container 1 signal.  This can be accomplished in Formula, using the following syntax:

//Create intermediate conditions for each error

$error1=$errorCond.keep('value',isEqualTo('44'))

$error2=$errorCond.keep('value',isEqualTo('47’))

 //Combine the 2 intermediate conditions

$error1.combineWith($error2)

 

3. Assign a ‘Container’ capsule property to each of the capsules in the Error Cond 1 condition that indicates the value of the Container 1 signal.  This can be accomplished within Formula, using the following syntax:

$errorCond1.removeLongerThan(1week).transform($capsule ->

        $capsule.setProperty('can', $container1.average($capsule)))

4. Repeat Steps 2&3 for Container 2

     a. Filter the condition created in Step 1 to only include capsules with errors of interest for Container 2.  This can be accomplished in Formula, using the following syntax:

         $errorCond.keep('value',isEqualTo('45'))

     b. Assign a ‘container’ capsule property to each of the capsules in the Error Cond 2 condition that indicates the value of the Container 2 signal.  This can be accomplished within Formula, using the following syntax:

       $errorCond2.removeLongerThan(1week).transform($capsule ->

                                  $capsule.setProperty('container', $container2.average($capsule)))

 

5. Combine the error conditions with container property to create a single, composite condition.  This can be performed in the Composite Condition tool.

6. Finally, create the histogram based upon this composite condition.

 

[Lindsey.Wilcox]

Since posting this solution, the Formula provided in Step 4B has been simplified to:

$errorCond2.removeLongerThan(1week).setProperty('container', $container2, startValue())