public class StandardDeviationVisitor extends Object implements FeatureCalc, FeatureAttributeVisitor
---------------------------- | 1 --- Std dev = | ___ \ ( x - mean ) ^ 2 \| N /__aka std dev = sqrt((sum((x-mean)^2))/N) where N is the number of samples.
It uses the rolling variance algorithm described here: http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#On-line_algorithm
Modifier and Type | Class and Description |
---|---|
static class |
StandardDeviationVisitor.Result |
Constructor and Description |
---|
StandardDeviationVisitor(Expression expr)
Constructs a standard deviation visitor based on the specified expression
|
StandardDeviationVisitor(Expression expr,
double average)
Deprecated.
use
StandardDeviationVisitor(Expression) insteads |
Modifier and Type | Method and Description |
---|---|
List<Expression> |
getExpressions()
List of expressions used by visitor.
|
double |
getMean()
mean value generated when calcualting standard deviation
|
int |
getNaNCount() |
int |
getNullCount() |
CalcResult |
getResult()
Returns the result of the calculation as a handy object which can be merged and modified.
|
void |
init(SimpleFeatureCollection collection) |
void |
reset() |
void |
visit(Feature feature)
Visit the provided feature.
|
void |
visit(SimpleFeature feature) |
@Deprecated public StandardDeviationVisitor(Expression expr, double average)
StandardDeviationVisitor(Expression)
insteadsexpr
- average
- public StandardDeviationVisitor(Expression expr)
expr
- average
- public void init(SimpleFeatureCollection collection)
public List<Expression> getExpressions()
FeatureAttributeVisitor
getExpressions
in interface FeatureAttributeVisitor
public CalcResult getResult()
FeatureCalc
getResult
in interface FeatureCalc
public void visit(SimpleFeature feature)
public void visit(Feature feature)
FeatureVisitor
Please consult the documentation for the FeatureCollection you are visiting to learn more - the provided feature may be invalid, or read only.
visit
in interface FeatureVisitor
public void reset()
public double getMean()
public int getNaNCount()
public int getNullCount()
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