Package com.singularsys.jep.functions

Class Round

java.lang.Object

com.singularsys.jep.functions.PostfixMathCommand

com.singularsys.jep.functions.NaryFunction

com.singularsys.jep.functions.Round

All Implemented Interfaces:

PostfixMathCommandI, Serializable

Direct Known Subclasses:

BigDecRound, RInt, RoundBD

public class Round
extends NaryFunction

A PostfixMathCommandI which rounds a number. The single argument version, round(a), uses Math.round(double) to round to the closest integer. The two argument version round(a,3) rounds the argument to 3 decimal places.

Note: This class was changed in version 3.4. Prior to 3.4, this class used the Math.rint method. In 3.4 and future releases Math.round will be used instead. The effect is changing the rounding behaviour when the input is equally close to two integers, Math.round rounds 1.5 down and Math.rint round it up.

In Jep 4.1 fixes a bug with round(100000,-5) -> 99999.99999999999. An alternative algorithm is provided by the RoundBD class, this uses BigDecimal's setscale(scale,mode) method. This can improve results for cases like round(265.335,2) where the floating-point representation of 265.335 is not exact.

Author:

Richard Morris

See Also:

• RInt
• RoundBD
• Serialized Form

Field Summary

Fields inherited from class com.singularsys.jep.functions.PostfixMathCommand

curNumberOfParameters, description, name, NaN, numberOfParameters

Constructor Summary

Constructors

Constructor	Description
Round()

Method Summary

Modifier and Type	Method	Description
boolean	checkNumberOfParameters(int n)	Must have one or two parameter
Object	eval(Object[] args)	Evaluate the function
protected double	round(double val)	The rounding method which implements the core rounding operation used in this class.
Object	round(Object param)
Object	round(Object l, Object r)
void	run(Stack<Object> inStack)	Creates an array of object then calls NaryFunction.eval(Object[])

Methods inherited from class com.singularsys.jep.functions.PostfixMathCommand

asArray, asBool, asDouble, asInt, asLong, asStrictInt, asString, asType, getDescription, getDescription, getDescriptionWithType, getName, getNumberOfParameters, setCurNumberOfParameters, setDescription, setName, toString, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

Round

public Round()

Method Details

checkNumberOfParameters

public boolean checkNumberOfParameters(int n)

Must have one or two parameter

Specified by:

checkNumberOfParameters in interface PostfixMathCommandI

Overrides:

checkNumberOfParameters in class PostfixMathCommand

Parameters:

n - number of parameters function will be called with.

Returns:

false if an illegal number of parameters is supplied, true otherwise.

run

public void run(Stack<Object> inStack)
         throws EvaluationException

Description copied from class: NaryFunction

Creates an array of object then calls NaryFunction.eval(Object[])

Specified by:

run in interface PostfixMathCommandI

Overrides:

run in class NaryFunction

Parameters:

inStack - arguments for function

Throws:

EvaluationException - if function cannot be evaluated

round

public Object round(Object l,
 Object r)
             throws EvaluationException

Throws:

EvaluationException

round

public Object round(Object param)
             throws EvaluationException

Throws:

EvaluationException

round

protected double round(double val)

The rounding method which implements the core rounding operation used in this class. Other subclasses (such as RInt) can override this to perform custom rounding.

Parameters:

val - number to round

Returns:

the rounded value

Since:

3.4.0

eval

public Object eval(Object[] args)
            throws EvaluationException

Description copied from class: NaryFunction

Evaluate the function

Specified by:

eval in class NaryFunction

Parameters:

args - arguments to the function

Returns:

value returned by the function

Throws:

EvaluationException - if the calculation cannot be performed