Developing Apama Applications > Developing Apama Applications in Event Modeler > Using Standard Blocks > General analytic blocks > Data Distribution Calculator v2.0
Data Distribution Calculator v2.0
The Data Distribution Calculator block calculates some common statistics from a set of samples. Like the correlation block, the set of samples may be unlimited in size, or constrained by a maximum number of samples or a maximum age of samples. Note that execution of the Median and Mode Calculator block, Moving Average block or Statistics Calculator block is faster than execution of the Data Distribution Calculator block. This is because those blocks perform a subset of the processing of the Data Distribution Calculator block.
Parameters
Parameter
Description
period
The maximum age of any sample that is used in the calculations, in seconds. Any samples older than this will be discarded before performing the calculation.
size
The maximum number of samples that are used in the calculation. The oldest sample is replaced by the newest sample when the total number of samples has reached this limit.
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 not impose any limit on the number of samples (thus an infinite set of samples is kept).
Operations
Operation
Description
start
Starts the calculation of statistics. Must be called before the calculator will generate any statistics.
stop
Stops the calculation of further statistics. Any subsequent input feeds are ignored.
clear
Discards all current data.
Input feeds
Feed
Fields
Description
data
value
The feed of values. The time of a value is taken to be the correlator’s current time.
Output feeds
Feed
Fields
Description
statistics
value
The most recent value received in the input feed.
mean
The arithmetic mean of the distribution.
mode
The most commonly occurring value, if there is one.
no unique mode
true if there is no single mode.
median
The mid point of the ordered set of data values.
standard deviation
Standard deviation of the data set.
variance
Variance of the distribution.
skew
Degree of skewed-ness of the distribution.
kurtosis
Kurtosis measure of the distribution.
samples
The number of samples used for this calculation.
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