Statistics Calculator v1.0

The Statistics Calculator block calculates running 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. The Statistics Calculator block performs a subset of the processing performed by the Data Distribution Calculator block. Consequently, execution of the Statistics Calculator block is considerably faster than execution 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 on the input feed. |

mean | The arithmetic mean of the data set. | |

standard deviation | Standard deviation of the data set. | |

variance | Variance of the data set. | |

skew | Degree of skewed-ness of the data set. | |

kurtosis | Kurtosis measure of the data set. | |

samples | The number of samples used for this calculation. |