ParameterPerturbation (OpenGamma Strata)

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
```
@FunctionalInterface
public interface ParameterPerturbation
```
A function interface that allows a single parameter to be perturbed.
This interface is used by ParameterizedData to allow parameters to be efficiently perturbed (altered). The method is invoked with the parameter index, value and metadata, and must return the new value.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`double`	`perturbParameter(int index, double value, ParameterMetadata metadata)`	Applies a perturbation to a single parameter.

- Method Detail
  - perturbParameter
```
double perturbParameter(int index,
                        double value,
                        ParameterMetadata metadata)
```
    Applies a perturbation to a single parameter.
    This method receives three arguments describing a single parameter, the index, current value and metadata. The result is the perturbed value.
    
    Parameters:
    
    index - the parameter index
    
    value - the parameter value
    
    metadata - the parameter metadata
    
    Returns:
    
    the perturbed value