Package com.singularsys.extensions.lambda

Class LambdaFunGenerator

java.lang.Object

com.singularsys.jep.functions.PostfixMathCommand

com.singularsys.extensions.lambda.LambdaFunGenerator

All Implemented Interfaces:

CallbackEvaluationI, JepComponent, PostfixMathCommandI, Serializable

public class LambdaFunGenerator
extends PostfixMathCommand
implements CallbackEvaluationI, JepComponent

Jep Function that generates a LambdaFunction. The lambda definition operator such as => defined in LambdaOperatorTable uses this class for its implementation. In the expression vars => expr, the left hand argument is the argument or list of arguments, and the right hand argument an expression, using these variable, for example:

x => x^2
[x,y] => x*y
[[x1,x2],[y1,y2]] => x1*y1+x2*y2
[u,v] => u[1]*v[1]+u[2]*v[2]

The last two expressions implement a dot product of two vectors, The first decomposes the vectors into their components, and the second uses indexing.

The names of the generated functions is specified using the com.singularsys.extensions.lambda.LambdaFunGenerator.nameFormat message property, and a unique instance number. The default format is lambda1.

Since Jep 4.1, extensions 2.2 pattern matching of vectors has been implemented. Nested lambda functions are now

See Also:

• Serialized Form

Field Summary

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

curNumberOfParameters, description, name, NaN, numberOfParameters

Constructor Summary

Constructors

Constructor	Description
LambdaFunGenerator()

Method Summary

Modifier and Type	Method	Description
Object	evaluate(Node node, Evaluator ev)	The evaluate method generates a LambdaFunction from a node tree.
JepComponent	getLightWeightInstance()	Gets a light-weight instance suitable for using in multiple threads.
void	init(Jep jep)	Initialize the component.

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

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

Methods inherited from class java.lang.Object

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

Constructor Details

LambdaFunGenerator

public LambdaFunGenerator()

Method Details

init

public void init(Jep jep)

Description copied from interface: JepComponent

Initialize the component. This method is called whenever a component is added to Jep. Hence, it allows components to keep track of the other components they may rely on.

Specified by:

init in interface JepComponent

Parameters:

jep - the current Jep instance

evaluate

public Object evaluate(Node node,
 Evaluator ev)
                throws EvaluationException

The evaluate method generates a LambdaFunction from a node tree.

Specified by:

evaluate in interface CallbackEvaluationI

Parameters:

node - the node tree of the expression

ev - the evaluator

Returns:

a LambdaFunction.

Throws:

EvaluationException - if the calculation cannot be performed

See Also:

• Evaluator

getLightWeightInstance

public JepComponent getLightWeightInstance()

Description copied from interface: JepComponent

Gets a light-weight instance suitable for using in multiple threads.

Specified by:

getLightWeightInstance in interface JepComponent

Returns:

either a new instance, null or 'this'.