ParameterDriver (ORbit Extrapolation KIT 11.0 API)

java.lang.Object
- org.orekit.utils.ParameterDriver

Direct Known Subclasses:

ParameterDriversList.DelegatingDriver
```
public class ParameterDriver
extends Object
```
Class allowing to drive the value of a parameter.
This class is typically used as a bridge between an estimation algorithm (typically orbit determination or optimizer) and an internal parameter in a physical model that needs to be tuned, or a bridge between a finite differences algorithm and an internal parameter in a physical model that needs to be slightly offset. The physical model will expose to the algorithm a set of instances of this class so the algorithm can call the setValue(double) method to update the parameter value. Each time the value is set, the physical model will be notified as it will register a ParameterObserver for this purpose.

This design has two major goals. First, it allows an external algorithm to drive internal parameters almost anonymously, as it only needs to get a list of instances of this class, without knowing what they really drive. Second, it allows the physical model to not expose directly setters methods for its parameters. In order to be able to modify the parameter value, the algorithm must retrieve a parameter driver.

Since:

8.0

Author:

Luc Maisonobe

See Also:

ParameterObserver

Constructor Summary

Constructors
Constructor and Description
`ParameterDriver(String name, double referenceValue, double scale, double minValue, double maxValue)` Simple constructor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addObserver(ParameterObserver observer)` Add an observer for this driver.
`double`	`getMaxValue()` Get maximum parameter value.
`double`	`getMinValue()` Get minimum parameter value.
`String`	`getName()` Get name.
`double`	`getNormalizedValue()` Get normalized value.
`List<ParameterObserver>`	`getObservers()` Get the observers for this driver.
`AbsoluteDate`	`getReferenceDate()` Get current reference date.
`double`	`getReferenceValue()` Get reference parameter value.
`double`	`getScale()` Get scale.
`double`	`getValue()` Get current parameter value.
`Gradient`	`getValue(int freeParameters, Map<String,Integer> indices)` Get the value as a gradient.
`boolean`	`isSelected()` Check if parameter is selected.
`void`	`removeObserver(ParameterObserver observer)` Remove an observer.
`void`	`replaceObserver(ParameterObserver oldObserver, ParameterObserver newObserver)` Replace an observer.
`void`	`setMaxValue(double maxValue)` Set maximum parameter value.
`void`	`setMinValue(double minValue)` Set minimum parameter value.
`void`	`setName(String name)` Change the name of this parameter driver.
`void`	`setNormalizedValue(double normalized)` Set normalized value.
`void`	`setReferenceDate(AbsoluteDate newReferenceDate)` Set reference date.
`void`	`setReferenceValue(double referenceValue)` Set reference parameter value.
`void`	`setScale(double scale)` Set scale.
`void`	`setSelected(boolean selected)` Configure a parameter selection status.
`void`	`setValue(double newValue)` Set parameter value.
`String`	`toString()` Get a text representation of the parameter.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - ParameterDriver
```
public ParameterDriver(String name,
                       double referenceValue,
                       double scale,
                       double minValue,
                       double maxValue)
```
    Simple constructor.
    At construction, the parameter is configured as not selected, the reference date is set to null and the value is set to the referenceValue.
    
    Parameters:
    
    name - name of the parameter
    
    referenceValue - reference value of the parameter
    
    scale - scaling factor to convert the parameters value to non-dimensional (typically set to the expected standard deviation of the parameter), it must be non-zero
    
    minValue - minimum value
    
    maxValue - maximum value
- Method Detail
  - addObserver
```
public void addObserver(ParameterObserver observer)
```
    Add an observer for this driver.
    The observer valueChanged method is called once automatically when the observer is added, and then called at each value change.
    
    Parameters:
    
    observer - observer to add while being updated
  - removeObserver
```
public void removeObserver(ParameterObserver observer)
```
    Remove an observer.
    
    Parameters:
    
    observer - observer to remove
    
    Since:
    
    9.1
  - replaceObserver
```
public void replaceObserver(ParameterObserver oldObserver,
                            ParameterObserver newObserver)
```
    Replace an observer.
    
    Parameters:
    
    oldObserver - observer to replace
    
    newObserver - new observer to use
    
    Since:
    
    10.1
  - getObservers
```
public List<ParameterObserver> getObservers()
```
    Get the observers for this driver.
    
    Returns:
    
    an unmodifiable view of the observers for this driver
    
    Since:
    
    9.1
  - setName
```
public void setName(String name)
```
    Change the name of this parameter driver.
    
    Parameters:
    
    name - new name
  - getName
```
public String getName()
```
    Get name.
    
    Returns:
    
    name
  - getReferenceValue
```
public double getReferenceValue()
```
    Get reference parameter value.
    
    Returns:
    
    reference parameter value
  - setReferenceValue
```
public void setReferenceValue(double referenceValue)
```
    Set reference parameter value.
    
    Parameters:
    
    referenceValue - the reference value to set.
    
    Since:
    
    9.3
  - getMinValue
```
public double getMinValue()
```
    Get minimum parameter value.
    
    Returns:
    
    minimum parameter value
  - setMinValue
```
public void setMinValue(double minValue)
```
    Set minimum parameter value.
    
    Parameters:
    
    minValue - the minimum value to set.
    
    Since:
    
    9.3
  - getMaxValue
```
public double getMaxValue()
```
    Get maximum parameter value.
    
    Returns:
    
    maximum parameter value
  - setMaxValue
```
public void setMaxValue(double maxValue)
```
    Set maximum parameter value.
    
    Parameters:
    
    maxValue - the maximum value to set.
    
    Since:
    
    9.3
  - getScale
```
public double getScale()
```
    Get scale.
    
    Returns:
    
    scale
  - setScale
```
public void setScale(double scale)
```
    Set scale.
    
    Parameters:
    
    scale - the scale to set.
    
    Since:
    
    9.3
  - getNormalizedValue
```
public double getNormalizedValue()
```
    Get normalized value.
    The normalized value is a non-dimensional value suitable for use as part of a vector in an optimization process. It is computed as (current - reference)/scale.
    
    Returns:
    
    normalized value
  - setNormalizedValue
```
public void setNormalizedValue(double normalized)
```
    Set normalized value.
    The normalized value is a non-dimensional value suitable for use as part of a vector in an optimization process. It is computed as (current - reference)/scale.
    
    Parameters:
    
    normalized - value
  - getReferenceDate
```
public AbsoluteDate getReferenceDate()
```
    Get current reference date.
    
    Returns:
    
    current reference date (null if it was never set)
    
    Since:
    
    9.0
  - setReferenceDate
```
public void setReferenceDate(AbsoluteDate newReferenceDate)
```
    Set reference date.
    
    Parameters:
    
    newReferenceDate - new reference date
    
    Since:
    
    9.0
  - getValue
```
public double getValue()
```
    Get current parameter value.
    
    Returns:
    
    current parameter value
  - getValue
```
public Gradient getValue(int freeParameters,
                         Map<String,Integer> indices)
```
    Get the value as a gradient.
    
    Parameters:
    
    freeParameters - total number of free parameters in the gradient
    
    indices - indices of the differentiation parameters in derivatives computations
    
    Returns:
    
    value with derivatives
    
    Since:
    
    10.2
  - setValue
```
public void setValue(double newValue)
```
    Set parameter value.
    If newValue is below getMinValue(), it will be silently set to getMinValue(). If newValue is above getMaxValue(), it will be silently set to getMaxValue().
    
    Parameters:
    
    newValue - new value
  - setSelected
```
public void setSelected(boolean selected)
```
    Configure a parameter selection status.
    Selection is used for estimated parameters in orbit determination, or to compute the Jacobian matrix in partial derivatives computation.
    
    Parameters:
    
    selected - if true the parameter is selected, otherwise it will be fixed
  - isSelected
```
public boolean isSelected()
```
    Check if parameter is selected.
    Selection is used for estimated parameters in orbit determination, or to compute the Jacobian matrix in partial derivatives computation.
    
    Returns:
    
    true if parameter is selected, false if it is not
  - toString
```
public String toString()
```
    Get a text representation of the parameter.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    text representation of the parameter, in the form name = value.

Class ParameterDriver

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

ParameterDriver

Method Detail

addObserver

removeObserver

replaceObserver

getObservers

setName

getName

getReferenceValue

setReferenceValue

getMinValue

setMinValue

getMaxValue

setMaxValue

getScale

setScale

getNormalizedValue

setNormalizedValue

getReferenceDate

setReferenceDate

getValue

getValue

setValue

setSelected

isSelected

toString