Description of the Correlation Calculator block interface
The Correlation Calculator block has the following parameters:
One or both of the above parameters must be 0, in which case that limit is not imposed. It is not possible to restrict the number of samples by both age and number of samples, but it is possible to remove the limit on the number of samples (thus an unbounded set of samples is kept). Note that imposing a limit after input events have been received will clear all existing samples.
The Correlation Calculator block has the following operations:
The Correlation Calculator block defines the following input feeds, each with one field:
Note that at least one value from each feed must have been received (and if set, within period seconds) before an output will be generated.
The Correlation Calculator block has the following output feed:
The XML elements at the beginning of the Correlation Calculator’s block definition file describe this interface. When you create your own block, Apama Studio generates and populates these XML elements for you.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE block SYSTEM "http://www.apama.com/dtd/bdf.dtd">
<!--Apama Block Definition File-->
<block name="Correlation Calculator">
<version>
<id>2.0</id>
<date>7 May 2009</date>
<author>Rune Madsen</author>
<comments>Copyright(c) 2013 Software AG, Darmstadt, Germany and/or its licensors</comments>
</version>
<description>Calculates the correlation of two input data streams over a configurable
time window and sample set size.</description>
<properties parallel-aware="true" deprecated="false">
<input-feeds>
<feed name="data1" id="9578163894100102">
<description>The first stream of numeric data to use in the correlation
calculations</description>
<field name="value" id="9578163894100103">
<description>The numeric data value</description>
<validation type="float" stringcase="mixed" trim="true" unique="false"
mutability="mutable" />
</field>
</feed>
<feed name="data2" id="9578163894100104">
<description>The second stream of numeric data to use in the correlation
calculations</description>
<field name="value" id="9578163894100105">
<description>The numeric data value</description>
<validation type="float" stringcase="mixed" trim="true" unique="false"
mutability="mutable" />
</field>
</feed>
</input-feeds>
<output-feeds>
<feed name="statistics" id="9578163894100106">
<description>Stream of correlation values generated every time a new data item
arrives</description>
<field name="correlation" id="9578163894100107">
<description>The correlation of the samples in the data sets. Between -1 and
+1.</description>
<validation type="float" stringcase="mixed" trim="true" unique="false"
mutability="mutable" />
</field>
<field name="samples" id="9578163894100108">
<description>The number of sample pairs used in the correlation
calculation</description>
<validation type="integer" stringcase="mixed" trim="true" unique="false"
mutability="mutable" />
</field>
</feed>
</output-feeds>
<parameters>
<field name="period" id="9578163894100109">
<description>The duration of the configurable time window given in seconds.
Samples older than the period will be discarded from the data set. Set to zero
to keep samples indefinitely, up to the maximum number of samples specified
with the size parameter.</description>
<validation type="float" stringcase="mixed" trim="true" unique="false"
mutability="mutable" />
</field>
<field name="size" id="9578163894100110">
<description>The maximum size of the sample set. The oldest sample will be
replaced by the new sample when the total number of samples has reached this
limit. Set to zero to keep all samples, unless period is set.</description>
<validation type="integer" stringcase="mixed" trim="true" unique="false"
mutability="mutable" />
</field>
</parameters>
<operations>
<operation name="start" id="9578163894100111">
<description>Activate the correlation calculations</description>
</operation>
<operation name="stop" id="9578163894100112">
<description>Pause the correlation calculations</description>
</operation>
<operation name="clear" id="9578163894100113">
<description>Clear the existing sample data</description>
</operation>
</operations>
</properties>