PipeLay > Excel Add-In > Function Reference > Statistics Functions

PURPOSE

Retrieve the Naive Standard Deviation for the specified parameters in the specified time range from the database.

The Naive Standard Deviation is a method used to calculate standard deviation using only a single pass. It is calculated as follows:

•Count the number of items in the specified range, n

•Sum the values of each item in the range, Sum

•Sum the square of each item in the range, SumSq

•Calculate the variance, var = ( SumSq - ( Sum2 ) / n) / n

•The Standard Deviation is calculated as √ var

This function will return a valid result when n > 1.

PLGetNaiveStandardDeviation( DatabaseName, StartTimeIndex, EndTimeIndex, ParameterType, ItemIndex, DOFNo )

DatabaseName (Character String)	The full path and filename to the relevant database. The file extension is optional.
StartTimeIndex (Integer)	The start time index, from 1 to the number of solutions in the database.
EndTimeIndex (Integer)	The end time index, from 1 to the number of solutions in the database. This should be a number higher than StartTimeIndex.
ParameterType (Integer)	The type of parameter to retrieve data for. See Parameter Types for a complete list.
ItemIndex (Integer)	The index of the required item. This is parameter dependent e.g. for kinematic parameters, this is a node number.
DOFNo (Integer)	The DOF or Local node number. This is parameter dependent so the ranges should correspond to what is valid for the parameter.

A numerical value containing the standard deviation for the specified parameters or one of the following error codes:

-999999998	Invalid Database.
-999999996	Invalid Parameter Number.
-999999995	Invalid Time Index. This may be either the start or end time.
-999999990	No Data Available.
-999999988	Item Index is out of range.
-999999985	Local Node Number or DOF is out of range.
-999999980	General Read Error.
-999999979	PLGetNaiveStandardDeviation function failed. Use the PLGetStandardDeviation function instead.