PLGetStandardDeviation

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PLGetStandardDeviation

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PURPOSE

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

HOW IS THIS CALCULATED?

The Standard Deviation is calculated in 2 passes. It is calculated as follows:

Calculate the mean of the values in the range. This is pass 1.

Count the number of items in the specified range, n

For the values in the range, sum the values as sum = sum + ( value - mean)2

Calculate the variance, var = sum / n

The Standard Deviation is calculated as √ var

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

SYNTAX

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

PARAMETERS

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.

OUTPUT

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.

SEE ALSO

Error Codes

Parameters

PLGetEnvelopeData

PLGetMaximumValue

PLGetMeanValue

PLGetMedian

PLGetMinimumValue

PLGetNaiveStandardDeviation

PLGetMode

PLGetRangeValue

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