casacore::TableExprGroupVarianceDouble Class Reference

Aggregate class determining the variance of values in a group. More...

#include <ExprGroupAggrFunc.h>

Inheritance diagram for casacore::TableExprGroupVarianceDouble:

List of all members.

Public Member Functions
	TableExprGroupVarianceDouble (TableExprNodeRep *node)
virtual	~TableExprGroupVarianceDouble ()
virtual void	apply (const TableExprId &id)
	Get the operand's value for the given row and apply it to the aggregation.
virtual void	finish ()
	If needed, finish the aggregation.
Protected Attributes
Int64	itsNr
Double	itsM2

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Detailed Description

Aggregate class determining the variance of values in a group.

Intended use:

Internal

Review Status

Test programs:

tExprGroup

Synopsis

Aggregate class determining the variance of values in a group. It uses a running algorithm (see en.wikipedia.org/wiki/Algorithms_for_calculating_variance)

Definition at line 352 of file ExprGroupAggrFunc.h.

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Constructor & Destructor Documentation

casacore::TableExprGroupVarianceDouble::TableExprGroupVarianceDouble

(

TableExprNodeRep *

node

)

[explicit]

virtual casacore::TableExprGroupVarianceDouble::~TableExprGroupVarianceDouble

(

)

[virtual]

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Member Function Documentation

virtual void casacore::TableExprGroupVarianceDouble::apply

(

const TableExprId &

id

)

[virtual]

Get the operand's value for the given row and apply it to the aggregation.

This function should not be called for lazy classes.

Implements casacore::TableExprGroupFuncBase.

virtual void casacore::TableExprGroupVarianceDouble::finish

(

)

[virtual]

If needed, finish the aggregation.

By default nothing is done.

Reimplemented from casacore::TableExprGroupFuncBase.

Reimplemented in casacore::TableExprGroupStdDevDouble.

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Member Data Documentation

Double casacore::TableExprGroupVarianceDouble::itsM2 [protected]

Definition at line 361 of file ExprGroupAggrFunc.h.

Int64 casacore::TableExprGroupVarianceDouble::itsNr [protected]

Definition at line 360 of file ExprGroupAggrFunc.h.

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The documentation for this class was generated from the following file:

• casacore/tables/TaQL/ExprGroupAggrFunc.h