java.lang.Object
- org.apache.commons.math3.util.ResizableDoubleArray

All Implemented Interfaces:

java.io.Serializable, DoubleArray
```
public class ResizableDoubleArray
extends java.lang.Object
implements DoubleArray, java.io.Serializable
```
A variable length DoubleArray implementation that automatically handles expanding and contracting its internal storage array as elements are added and removed.

Important note: Usage should not assume that this class is thread-safe even though some of the methods are synchronized. This qualifier will be dropped in the next major release (4.0).

The internal storage array starts with capacity determined by the initialCapacity property, which can be set by the constructor. The default initial capacity is 16. Adding elements using addElement(double) appends elements to the end of the array. When there are no open entries at the end of the internal storage array, the array is expanded. The size of the expanded array depends on the expansionMode and expansionFactor properties. The expansionMode determines whether the size of the array is multiplied by the expansionFactor (ResizableDoubleArray.ExpansionMode.MULTIPLICATIVE) or if the expansion is additive (ResizableDoubleArray.ExpansionMode.ADDITIVE -- expansionFactor storage locations added). The default expansionMode is MULTIPLICATIVE and the default expansionFactor is 2.

The addElementRolling(double) method adds a new element to the end of the internal storage array and adjusts the "usable window" of the internal array forward by one position (effectively making what was the second element the first, and so on). Repeated activations of this method (or activation of discardFrontElements(int)) will effectively orphan the storage locations at the beginning of the internal storage array. To reclaim this storage, each time one of these methods is activated, the size of the internal storage array is compared to the number of addressable elements (the numElements property) and if the difference is too large, the internal array is contracted to size numElements + 1. The determination of when the internal storage array is "too large" depends on the expansionMode and contractionFactor properties. If the expansionMode is MULTIPLICATIVE, contraction is triggered when the ratio between storage array length and numElements exceeds contractionFactor. If the expansionMode is ADDITIVE, the number of excess storage locations is compared to contractionFactor.

To avoid cycles of expansions and contractions, the expansionFactor must not exceed the contractionFactor. Constructors and mutators for both of these properties enforce this requirement, throwing a MathIllegalArgumentException if it is violated.

See Also:

Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class ResizableDoubleArray.ExpansionMode
Specification of expansion algorithm.

Field Summary

Fields
Modifier and Type	Field	Description
`static int`	`ADDITIVE_MODE`	Deprecated. As of 3.1.
`private double`	`contractionCriterion`	The contraction criteria determines when the internal array will be contracted to fit the number of elements contained in the element array + 1.
`private static double`	`DEFAULT_CONTRACTION_DELTA`	Default value for the difference between `contractionCriterion` and `expansionFactor`.
`private static double`	`DEFAULT_EXPANSION_FACTOR`	Default value for array size modifier.
`private static int`	`DEFAULT_INITIAL_CAPACITY`	Default value for initial capacity.
`private double`	`expansionFactor`	The expansion factor of the array.
`private ResizableDoubleArray.ExpansionMode`	`expansionMode`	Determines whether array expansion by `expansionFactor` is additive or multiplicative.
`private double[]`	`internalArray`	The internal storage array.
`static int`	`MULTIPLICATIVE_MODE`	Deprecated. As of 3.1.
`private int`	`numElements`	The number of addressable elements in the array.
`private static long`	`serialVersionUID`	Serializable version identifier.
`private int`	`startIndex`	The position of the first addressable element in the internal storage array.

Constructor Summary

Constructors
Constructor	Description
`ResizableDoubleArray()`	Creates an instance with default properties.
`ResizableDoubleArray(double[] initialArray)`	Creates an instance from an existing `double[]` with the initial capacity and numElements corresponding to the size of the supplied `double[]` array.
`ResizableDoubleArray(int initialCapacity)`	Creates an instance with the specified initial capacity.
`ResizableDoubleArray(int initialCapacity, double expansionFactor)`	Creates an instance with the specified initial capacity and expansion factor.
`ResizableDoubleArray(int initialCapacity, double expansionFactor, double contractionCriterion)`	Creates an instance with the specified initial capacity, expansion factor, and contraction criteria.
`ResizableDoubleArray(int initialCapacity, double expansionFactor, double contractionCriterion, ResizableDoubleArray.ExpansionMode expansionMode, double... data)`	Creates an instance with the specified properties.
`ResizableDoubleArray(int initialCapacity, float expansionFactor)`	Deprecated. As of 3.1.
`ResizableDoubleArray(int initialCapacity, float expansionFactor, float contractionCriteria)`	Deprecated. As of 3.1.
`ResizableDoubleArray(int initialCapacity, float expansionFactor, float contractionCriteria, int expansionMode)`	Deprecated. As of 3.1.
`ResizableDoubleArray(ResizableDoubleArray original)`	Copy constructor.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`void`	`addElement(double value)`	Adds an element to the end of this expandable array.
`double`	`addElementRolling(double value)`	Adds an element to the end of the array and removes the first element in the array.
`void`	`addElements(double[] values)`	Adds several element to the end of this expandable array.
`protected void`	`checkContractExpand(double contraction, double expansion)`	Checks the expansion factor and the contraction criterion and raises an exception if the contraction criterion is smaller than the expansion criterion.
`protected void`	`checkContractExpand(float contraction, float expansion)`	Deprecated. As of 3.1.
`void`	`clear()`	Clear the array contents, resetting the number of elements to zero.
`double`	`compute(MathArrays.Function f)`	Performs an operation on the addressable elements of the array.
`void`	`contract()`	Contracts the storage array to the (size of the element set) + 1 - to avoid a zero length array.
`ResizableDoubleArray`	`copy()`	Returns a copy of the ResizableDoubleArray.
`static void`	`copy(ResizableDoubleArray source, ResizableDoubleArray dest)`	Copies source to dest, copying the underlying data, so dest is a new, independent copy of source.
`private void`	`discardExtremeElements(int i, boolean front)`	Discards the `i` first or last elements of the array, depending on the value of `front`.
`void`	`discardFrontElements(int i)`	Discards the `i` initial elements of the array.
`void`	`discardMostRecentElements(int i)`	Discards the `i` last elements of the array.
`boolean`	`equals(java.lang.Object object)`	Returns true iff object is a ResizableDoubleArray with the same properties as this and an identical internal storage array.
`protected void`	`expand()`	Expands the internal storage array using the expansion factor.
`private void`	`expandTo(int size)`	Expands the internal storage array to the specified size.
`protected double[]`	`getArrayRef()`	Provides direct access to the internal storage array.
`int`	`getCapacity()`	Gets the currently allocated size of the internal data structure used for storing elements.
`float`	`getContractionCriteria()`	Deprecated. As of 3.1.
`double`	`getContractionCriterion()`	The contraction criterion defines when the internal array will contract to store only the number of elements in the element array.
`double`	`getElement(int index)`	Returns the element at the specified index
`double[]`	`getElements()`	Returns a double array containing the elements of this `ResizableArray`.
`float`	`getExpansionFactor()`	Deprecated. As of 3.1.
`int`	`getExpansionMode()`	Deprecated. As of 3.1.
`(package private) int`	`getInternalLength()`	Deprecated. As of 3.1.
`double[]`	`getInternalValues()`	Deprecated. As of 3.1.
`int`	`getNumElements()`	Returns the number of elements currently in the array.
`protected int`	`getStartIndex()`	Returns the "start index" of the internal array.
`int`	`hashCode()`	Returns a hash code consistent with equals.
`void`	`setContractionCriteria(float contractionCriteria)`	Deprecated. As of 3.1 (to be removed in 4.0 as field will become "final").
`void`	`setElement(int index, double value)`	Sets the element at the specified index.
`void`	`setExpansionFactor(float expansionFactor)`	Deprecated. As of 3.1 (to be removed in 4.0 as field will become "final").
`void`	`setExpansionMode(int expansionMode)`	Deprecated. As of 3.1.
`void`	`setExpansionMode(ResizableDoubleArray.ExpansionMode expansionMode)`	Deprecated. As of 3.1 (to be removed in 4.0 as field will become "final").
`protected void`	`setInitialCapacity(int initialCapacity)`	Deprecated. As of 3.1, this is a no-op.
`void`	`setNumElements(int i)`	This function allows you to control the number of elements contained in this array, and can be used to "throw out" the last n values in an array.
`private boolean`	`shouldContract()`	Returns true if the internal storage array has too many unused storage positions.
`int`	`start()`	Deprecated. As of 3.1.
`double`	`substituteMostRecentElement(double value)`	Substitutes `value` for the most recently added value.

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

- Field Detail
  - ADDITIVE_MODE
```
@Deprecated
public static final int ADDITIVE_MODE
```
    Deprecated.
    As of 3.1. Please use ResizableDoubleArray.ExpansionMode.ADDITIVE instead.
    
    Additive expansion mode.
    
    See Also:
    
    Constant Field Values
  - MULTIPLICATIVE_MODE
```
@Deprecated
public static final int MULTIPLICATIVE_MODE
```
    Deprecated.
    As of 3.1. Please use ResizableDoubleArray.ExpansionMode.MULTIPLICATIVE instead.
    
    Multiplicative expansion mode.
    
    See Also:
    
    Constant Field Values
  - serialVersionUID
```
private static final long serialVersionUID
```
    Serializable version identifier.
    
    See Also:
    
    Constant Field Values
  - DEFAULT_INITIAL_CAPACITY
```
private static final int DEFAULT_INITIAL_CAPACITY
```
    Default value for initial capacity.
    
    See Also:
    
    Constant Field Values
  - DEFAULT_EXPANSION_FACTOR
```
private static final double DEFAULT_EXPANSION_FACTOR
```
    Default value for array size modifier.
    
    See Also:
    
    Constant Field Values
  - DEFAULT_CONTRACTION_DELTA
```
private static final double DEFAULT_CONTRACTION_DELTA
```
    Default value for the difference between contractionCriterion and expansionFactor.
    
    See Also:
    
    Constant Field Values
  - contractionCriterion
```
private double contractionCriterion
```
    The contraction criteria determines when the internal array will be contracted to fit the number of elements contained in the element array + 1.
  - expansionFactor
```
private double expansionFactor
```
    The expansion factor of the array. When the array needs to be expanded, the new array size will be internalArray.length * expansionFactor if expansionMode is set to MULTIPLICATIVE_MODE, or internalArray.length + expansionFactor if expansionMode is set to ADDITIVE_MODE.
  - expansionMode
```
private ResizableDoubleArray.ExpansionMode expansionMode
```
    Determines whether array expansion by expansionFactor is additive or multiplicative.
  - internalArray
```
private double[] internalArray
```
    The internal storage array.
  - numElements
```
private int numElements
```
    The number of addressable elements in the array. Note that this has nothing to do with the length of the internal storage array.
  - startIndex
```
private int startIndex
```
    The position of the first addressable element in the internal storage array. The addressable elements in the array are internalArray[startIndex],...,internalArray[startIndex + numElements - 1].
- Constructor Detail
  - ResizableDoubleArray
```
public ResizableDoubleArray()
```
    Creates an instance with default properties.
    
    initialCapacity = 16
    
    expansionMode = MULTIPLICATIVE
    
    expansionFactor = 2.0
    
    contractionCriterion = 2.5
  - ResizableDoubleArray
```
public ResizableDoubleArray(int initialCapacity)
                     throws MathIllegalArgumentException
```
    Creates an instance with the specified initial capacity. Other properties take default values:
    
    expansionMode = MULTIPLICATIVE
    
    expansionFactor = 2.0
    
    contractionCriterion = 2.5
    Parameters:
    
    initialCapacity - Initial size of the internal storage array.
    
    Throws:
    
    MathIllegalArgumentException - if initialCapacity <= 0.
  - ResizableDoubleArray
```
public ResizableDoubleArray(double[] initialArray)
```
    Creates an instance from an existing double[] with the initial capacity and numElements corresponding to the size of the supplied double[] array. If the supplied array is null, a new empty array with the default initial capacity will be created. The input array is copied, not referenced. Other properties take default values:
    
    initialCapacity = 16
    
    expansionMode = MULTIPLICATIVE
    
    expansionFactor = 2.0
    
    contractionCriterion = 2.5
    Parameters:
    
    initialArray - initial array
    
    Since:
    
    2.2
  - ResizableDoubleArray
```
@Deprecated
public ResizableDoubleArray(int initialCapacity,
                            float expansionFactor)
                     throws MathIllegalArgumentException
```
    Deprecated.
    As of 3.1. Please use ResizableDoubleArray(int,double) instead.
    Creates an instance with the specified initial capacity and expansion factor. The remaining properties take default values:
    
    expansionMode = MULTIPLICATIVE
    
    contractionCriterion = 0.5 + expansionFactor
    
    Throws IllegalArgumentException if the following conditions are not met:
    
    initialCapacity > 0
    
    expansionFactor > 1
    Parameters:
    
    initialCapacity - Initial size of the internal storage array.
    
    expansionFactor - The array will be expanded based on this parameter.
    
    Throws:
    
    MathIllegalArgumentException - if parameters are not valid.
  - ResizableDoubleArray
```
public ResizableDoubleArray(int initialCapacity,
                            double expansionFactor)
                     throws MathIllegalArgumentException
```
    Creates an instance with the specified initial capacity and expansion factor. The remaining properties take default values:
    
    expansionMode = MULTIPLICATIVE
    
    contractionCriterion = 0.5 + expansionFactor
    
    Throws IllegalArgumentException if the following conditions are not met:
    
    initialCapacity > 0
    
    expansionFactor > 1
    Parameters:
    
    initialCapacity - Initial size of the internal storage array.
    
    expansionFactor - The array will be expanded based on this parameter.
    
    Throws:
    
    MathIllegalArgumentException - if parameters are not valid.
    
    Since:
    
    3.1
  - ResizableDoubleArray
```
@Deprecated
public ResizableDoubleArray(int initialCapacity,
                            float expansionFactor,
                            float contractionCriteria)
                     throws MathIllegalArgumentException
```
    Deprecated.
    As of 3.1. Please use ResizableDoubleArray(int,double,double) instead.
    Creates an instance with the specified initialCapacity, expansionFactor, and contractionCriterion. The expansion mode will default to MULTIPLICATIVE.
    Throws IllegalArgumentException if the following conditions are not met:
    
    initialCapacity > 0
    
    expansionFactor > 1
    
    contractionCriterion >= expansionFactor
    Parameters:
    
    initialCapacity - Initial size of the internal storage array..
    
    expansionFactor - The array will be expanded based on this parameter.
    
    contractionCriteria - Contraction criteria.
    
    Throws:
    
    MathIllegalArgumentException - if parameters are not valid.
  - ResizableDoubleArray
```
public ResizableDoubleArray(int initialCapacity,
                            double expansionFactor,
                            double contractionCriterion)
                     throws MathIllegalArgumentException
```
    Creates an instance with the specified initial capacity, expansion factor, and contraction criteria. The expansion mode will default to MULTIPLICATIVE.
    Throws IllegalArgumentException if the following conditions are not met:
    
    initialCapacity > 0
    
    expansionFactor > 1
    
    contractionCriterion >= expansionFactor
    Parameters:
    
    initialCapacity - Initial size of the internal storage array..
    
    expansionFactor - The array will be expanded based on this parameter.
    
    contractionCriterion - Contraction criterion.
    
    Throws:
    
    MathIllegalArgumentException - if the parameters are not valid.
    
    Since:
    
    3.1
  - ResizableDoubleArray
```
@Deprecated
public ResizableDoubleArray(int initialCapacity,
                            float expansionFactor,
                            float contractionCriteria,
                            int expansionMode)
                     throws MathIllegalArgumentException
```
    Deprecated.
    As of 3.1. Please use ResizableDoubleArray(int,double,double,ExpansionMode,double[]) instead.
    Create a ResizableArray with the specified properties.
    
    Throws IllegalArgumentException if the following conditions are not met:
    
    initialCapacity > 0
    
    expansionFactor > 1
    
    contractionFactor >= expansionFactor
    
    expansionMode in {MULTIPLICATIVE_MODE, ADDITIVE_MODE}
    Parameters:
    
    initialCapacity - the initial size of the internal storage array
    
    expansionFactor - the array will be expanded based on this parameter
    
    contractionCriteria - the contraction Criteria
    
    expansionMode - the expansion mode
    
    Throws:
    
    MathIllegalArgumentException - if parameters are not valid
  - ResizableDoubleArray
```
public ResizableDoubleArray(int initialCapacity,
                            double expansionFactor,
                            double contractionCriterion,
                            ResizableDoubleArray.ExpansionMode expansionMode,
                            double... data)
                     throws MathIllegalArgumentException
```
    Creates an instance with the specified properties.
    Throws MathIllegalArgumentException if the following conditions are not met:
    
    initialCapacity > 0
    
    expansionFactor > 1
    
    contractionCriterion >= expansionFactor
    Parameters:
    
    initialCapacity - Initial size of the internal storage array.
    
    expansionFactor - The array will be expanded based on this parameter.
    
    contractionCriterion - Contraction criteria.
    
    expansionMode - Expansion mode.
    
    data - Initial contents of the array.
    
    Throws:
    
    MathIllegalArgumentException - if the parameters are not valid.
  - ResizableDoubleArray
```
public ResizableDoubleArray(ResizableDoubleArray original)
                     throws NullArgumentException
```
    Copy constructor. Creates a new ResizableDoubleArray that is a deep, fresh copy of the original. Needs to acquire synchronization lock on original. Original may not be null; otherwise a NullArgumentException is thrown.
    
    Parameters:
    
    original - array to copy
    
    Throws:
    
    NullArgumentException - if original is null
    
    Since:
    
    2.0
- Method Detail
  - addElement
```
public void addElement(double value)
```
    Adds an element to the end of this expandable array.
    
    Specified by:
    
    addElement in interface DoubleArray
    
    Parameters:
    
    value - Value to be added to end of array.
  - addElements
```
public void addElements(double[] values)
```
    Adds several element to the end of this expandable array.
    
    Specified by:
    
    addElements in interface DoubleArray
    
    Parameters:
    
    values - Values to be added to end of array.
    
    Since:
    
    2.2
  - addElementRolling
```
public double addElementRolling(double value)
```
    Adds an element to the end of the array and removes the first element in the array. Returns the discarded first element. The effect is similar to a push operation in a FIFO queue.
    
    Example: If the array contains the elements 1, 2, 3, 4 (in that order) and addElementRolling(5) is invoked, the result is an array containing the entries 2, 3, 4, 5 and the value returned is 1.
    
    Specified by:
    
    addElementRolling in interface DoubleArray
    
    Parameters:
    
    value - Value to be added to the array.
    
    Returns:
    
    the value which has been discarded or "pushed" out of the array by this rolling insert.
  - substituteMostRecentElement
```
public double substituteMostRecentElement(double value)
                                   throws MathIllegalStateException
```
    Substitutes value for the most recently added value. Returns the value that has been replaced. If the array is empty (i.e. if numElements is zero), an IllegalStateException is thrown.
    
    Parameters:
    
    value - New value to substitute for the most recently added value
    
    Returns:
    
    the value that has been replaced in the array.
    
    Throws:
    
    MathIllegalStateException - if the array is empty
    
    Since:
    
    2.0
  - checkContractExpand
```
@Deprecated
protected void checkContractExpand(float contraction,
                                   float expansion)
                            throws MathIllegalArgumentException
```
    Deprecated.
    As of 3.1. Please use checkContractExpand(double,double) instead.
    
    Checks the expansion factor and the contraction criterion and throws an IllegalArgumentException if the contractionCriteria is less than the expansionCriteria
    
    Parameters:
    
    expansion - factor to be checked
    
    contraction - criteria to be checked
    
    Throws:
    
    MathIllegalArgumentException - if the contractionCriteria is less than the expansionCriteria.
  - checkContractExpand
```
protected void checkContractExpand(double contraction,
                                   double expansion)
                            throws NumberIsTooSmallException
```
    Checks the expansion factor and the contraction criterion and raises an exception if the contraction criterion is smaller than the expansion criterion.
    
    Parameters:
    
    contraction - Criterion to be checked.
    
    expansion - Factor to be checked.
    
    Throws:
    
    NumberIsTooSmallException - if contraction < expansion.
    
    NumberIsTooSmallException - if contraction <= 1.
    
    NumberIsTooSmallException - if expansion <= 1 .
    
    Since:
    
    3.1
  - clear
```
public void clear()
```
    Clear the array contents, resetting the number of elements to zero.
    
    Specified by:
    
    clear in interface DoubleArray
  - contract
```
public void contract()
```
    Contracts the storage array to the (size of the element set) + 1 - to avoid a zero length array. This function also resets the startIndex to zero.
  - discardFrontElements
```
public void discardFrontElements(int i)
                          throws MathIllegalArgumentException
```
    Discards the i initial elements of the array. For example, if the array contains the elements 1,2,3,4, invoking discardFrontElements(2) will cause the first two elements to be discarded, leaving 3,4 in the array. Throws illegalArgumentException if i exceeds numElements.
    
    Parameters:
    
    i - the number of elements to discard from the front of the array
    
    Throws:
    
    MathIllegalArgumentException - if i is greater than numElements.
    
    Since:
    
    2.0
  - discardMostRecentElements
```
public void discardMostRecentElements(int i)
                               throws MathIllegalArgumentException
```
    Discards the i last elements of the array. For example, if the array contains the elements 1,2,3,4, invoking discardMostRecentElements(2) will cause the last two elements to be discarded, leaving 1,2 in the array. Throws illegalArgumentException if i exceeds numElements.
    
    Parameters:
    
    i - the number of elements to discard from the end of the array
    
    Throws:
    
    MathIllegalArgumentException - if i is greater than numElements.
    
    Since:
    
    2.0
  - discardExtremeElements
```
private void discardExtremeElements(int i,
                                    boolean front)
                             throws MathIllegalArgumentException
```
    Discards the i first or last elements of the array, depending on the value of front. For example, if the array contains the elements 1,2,3,4, invoking discardExtremeElements(2,false) will cause the last two elements to be discarded, leaving 1,2 in the array. For example, if the array contains the elements 1,2,3,4, invoking discardExtremeElements(2,true) will cause the first two elements to be discarded, leaving 3,4 in the array. Throws illegalArgumentException if i exceeds numElements.
    
    Parameters:
    
    i - the number of elements to discard from the front/end of the array
    
    front - true if elements are to be discarded from the front of the array, false if elements are to be discarded from the end of the array
    
    Throws:
    
    MathIllegalArgumentException - if i is greater than numElements.
    
    Since:
    
    2.0
  - expand
```
protected void expand()
```
    Expands the internal storage array using the expansion factor.
    if expansionMode is set to MULTIPLICATIVE_MODE, the new array size will be internalArray.length * expansionFactor. If expansionMode is set to ADDITIVE_MODE, the length after expansion will be internalArray.length + expansionFactor
  - expandTo
```
private void expandTo(int size)
```
    Expands the internal storage array to the specified size.
    
    Parameters:
    
    size - Size of the new internal storage array.
  - getContractionCriteria
```
@Deprecated
public float getContractionCriteria()
```
    Deprecated.
    As of 3.1. Please use getContractionCriterion() instead.
    
    The contraction criteria defines when the internal array will contract to store only the number of elements in the element array. If the expansionMode is MULTIPLICATIVE_MODE, contraction is triggered when the ratio between storage array length and numElements exceeds contractionFactor. If the expansionMode is ADDITIVE_MODE, the number of excess storage locations is compared to contractionFactor.
    
    Returns:
    
    the contraction criteria used to reclaim memory.
  - getContractionCriterion
```
public double getContractionCriterion()
```
    The contraction criterion defines when the internal array will contract to store only the number of elements in the element array. If the expansionMode is MULTIPLICATIVE_MODE, contraction is triggered when the ratio between storage array length and numElements exceeds contractionFactor. If the expansionMode is ADDITIVE_MODE, the number of excess storage locations is compared to contractionFactor.
    
    Returns:
    
    the contraction criterion used to reclaim memory.
    
    Since:
    
    3.1
  - getElement
```
public double getElement(int index)
```
    Returns the element at the specified index
    
    Specified by:
    
    getElement in interface DoubleArray
    
    Parameters:
    
    index - index to fetch a value from
    
    Returns:
    
    value stored at the specified index
    
    Throws:
    
    java.lang.ArrayIndexOutOfBoundsException - if index is less than zero or is greater than getNumElements() - 1.
  - getElements
```
public double[] getElements()
```
    Returns a double array containing the elements of this ResizableArray. This method returns a copy, not a reference to the underlying array, so that changes made to the returned array have no effect on this ResizableArray.
    
    Specified by:
    
    getElements in interface DoubleArray
    
    Returns:
    
    the double array.
  - getExpansionFactor
```
@Deprecated
public float getExpansionFactor()
```
    Deprecated.
    As of 3.1. Return type will be changed to "double" in 4.0.
    
    The expansion factor controls the size of a new array when an array needs to be expanded. The expansionMode determines whether the size of the array is multiplied by the expansionFactor (MULTIPLICATIVE_MODE) or if the expansion is additive (ADDITIVE_MODE -- expansionFactor storage locations added). The default expansionMode is MULTIPLICATIVE_MODE and the default expansionFactor is 2.0.
    
    Returns:
    
    the expansion factor of this expandable double array
  - getExpansionMode
```
@Deprecated
public int getExpansionMode()
```
    Deprecated.
    As of 3.1. Return value to be changed to ResizableDoubleArray.ExpansionMode in 4.0.
    
    The expansion mode determines whether the internal storage array grows additively or multiplicatively when it is expanded.
    
    Returns:
    
    the expansion mode.
  - getInternalLength
```
@Deprecated
int getInternalLength()
```
    Deprecated.
    As of 3.1. Please use getCapacity() instead.
    
    Notice the package scope on this method. This method is simply here for the JUnit test, it allows us check if the expansion is working properly after a number of expansions. This is not meant to be a part of the public interface of this class.
    
    Returns:
    
    the length of the internal storage array.
  - getCapacity
```
public int getCapacity()
```
    Gets the currently allocated size of the internal data structure used for storing elements. This is not to be confused with the number of elements actually stored.
    
    Returns:
    
    the length of the internal array.
    
    Since:
    
    3.1
  - getNumElements
```
public int getNumElements()
```
    Returns the number of elements currently in the array. Please note that this is different from the length of the internal storage array.
    
    Specified by:
    
    getNumElements in interface DoubleArray
    
    Returns:
    
    the number of elements.
  - getInternalValues
```
@Deprecated
public double[] getInternalValues()
```
    Deprecated.
    As of 3.1.
    
    Returns the internal storage array. Note that this method returns a reference to the internal storage array, not a copy, and to correctly address elements of the array, the startIndex is required (available via the start() method). This method should only be used in cases where copying the internal array is not practical. The getElements() method should be used in all other cases.
    
    Returns:
    
    the internal storage array used by this object
    
    Since:
    
    2.0
  - getArrayRef
```
protected double[] getArrayRef()
```
    Provides direct access to the internal storage array. Please note that this method returns a reference to this object's storage array, not a copy.
    To correctly address elements of the array, the "start index" is required (available via the getStartIndex method.
    This method should only be used to avoid copying the internal array. The returned value must be used for reading only; other uses could lead to this object becoming inconsistent.
    The getElements() method has no such limitation since it returns a copy of this array's addressable elements.
    
    Returns:
    
    the internal storage array used by this object.
    
    Since:
    
    3.1
  - getStartIndex
```
protected int getStartIndex()
```
    Returns the "start index" of the internal array. This index is the position of the first addressable element in the internal storage array. The addressable elements in the array are at indices contained in the interval [getStartIndex(), getStartIndex() + getNumElements() - 1].
    
    Returns:
    
    the start index.
    
    Since:
    
    3.1
  - setContractionCriteria
```
@Deprecated
public void setContractionCriteria(float contractionCriteria)
                            throws MathIllegalArgumentException
```
    Deprecated.
    As of 3.1 (to be removed in 4.0 as field will become "final").
    
    Sets the contraction criteria.
    
    Parameters:
    
    contractionCriteria - contraction criteria
    
    Throws:
    
    MathIllegalArgumentException - if the contractionCriteria is less than the expansionCriteria.
  - compute
```
public double compute(MathArrays.Function f)
```
    Performs an operation on the addressable elements of the array.
    
    Parameters:
    
    f - Function to be applied on this array.
    
    Returns:
    
    the result.
    
    Since:
    
    3.1
  - setElement
```
public void setElement(int index,
                       double value)
```
    Sets the element at the specified index. If the specified index is greater than getNumElements() - 1, the numElements property is increased to index +1 and additional storage is allocated (if necessary) for the new element and all (uninitialized) elements between the new element and the previous end of the array).
    
    Specified by:
    
    setElement in interface DoubleArray
    
    Parameters:
    
    index - index to store a value in
    
    value - value to store at the specified index
    
    Throws:
    
    java.lang.ArrayIndexOutOfBoundsException - if index < 0.
  - setExpansionFactor
```
@Deprecated
public void setExpansionFactor(float expansionFactor)
                        throws MathIllegalArgumentException
```
    Deprecated.
    As of 3.1 (to be removed in 4.0 as field will become "final").
    Sets the expansionFactor. Throws IllegalArgumentException if the the following conditions are not met:
    
    expansionFactor > 1
    
    contractionFactor >= expansionFactor
    Parameters:
    
    expansionFactor - the new expansion factor value.
    
    Throws:
    
    MathIllegalArgumentException - if expansionFactor is <= 1 or greater than contractionFactor
  - setExpansionMode
```
@Deprecated
public void setExpansionMode(int expansionMode)
                      throws MathIllegalArgumentException
```
    Deprecated.
    As of 3.1. Please use setExpansionMode(ExpansionMode) instead.
    
    Sets the expansionMode. The specified value must be one of ADDITIVE_MODE, MULTIPLICATIVE_MODE.
    
    Parameters:
    
    expansionMode - The expansionMode to set.
    
    Throws:
    
    MathIllegalArgumentException - if the specified mode value is not valid.
  - setExpansionMode
```
@Deprecated
public void setExpansionMode(ResizableDoubleArray.ExpansionMode expansionMode)
```
    Deprecated.
    As of 3.1 (to be removed in 4.0 as field will become "final").
    
    Sets the expansion mode.
    
    Parameters:
    
    expansionMode - Expansion mode to use for resizing the array.
  - setInitialCapacity
```
@Deprecated
protected void setInitialCapacity(int initialCapacity)
                           throws MathIllegalArgumentException
```
    Deprecated.
    As of 3.1, this is a no-op.
    
    Sets the initial capacity. Should only be invoked by constructors.
    
    Parameters:
    
    initialCapacity - of the array
    
    Throws:
    
    MathIllegalArgumentException - if initialCapacity is not positive.
  - setNumElements
```
public void setNumElements(int i)
                    throws MathIllegalArgumentException
```
    This function allows you to control the number of elements contained in this array, and can be used to "throw out" the last n values in an array. This function will also expand the internal array as needed.
    
    Parameters:
    
    i - a new number of elements
    
    Throws:
    
    MathIllegalArgumentException - if i is negative.
  - shouldContract
```
private boolean shouldContract()
```
    Returns true if the internal storage array has too many unused storage positions.
    
    Returns:
    
    true if array satisfies the contraction criteria
  - start
```
@Deprecated
public int start()
```
    Deprecated.
    As of 3.1.
    
    Returns the starting index of the internal array. The starting index is the position of the first addressable element in the internal storage array. The addressable elements in the array are internalArray[startIndex],...,internalArray[startIndex + numElements -1]
    
    Returns:
    
    the starting index.
  - copy
```
public static void copy(ResizableDoubleArray source,
                        ResizableDoubleArray dest)
                 throws NullArgumentException
```
    Copies source to dest, copying the underlying data, so dest is a new, independent copy of source. Does not contract before the copy.
    
    Obtains synchronization locks on both source and dest (in that order) before performing the copy.
    
    Neither source nor dest may be null; otherwise a NullArgumentException is thrown
    
    Parameters:
    
    source - ResizableDoubleArray to copy
    
    dest - ResizableArray to replace with a copy of the source array
    
    Throws:
    
    NullArgumentException - if either source or dest is null
    
    Since:
    
    2.0
  - copy
```
public ResizableDoubleArray copy()
```
    Returns a copy of the ResizableDoubleArray. Does not contract before the copy, so the returned object is an exact copy of this.
    
    Returns:
    
    a new ResizableDoubleArray with the same data and configuration properties as this
    
    Since:
    
    2.0
  - equals
```
public boolean equals(java.lang.Object object)
```
    Returns true iff object is a ResizableDoubleArray with the same properties as this and an identical internal storage array.
    
    Overrides:
    
    equals in class java.lang.Object
    
    Parameters:
    
    object - object to be compared for equality with this
    
    Returns:
    
    true iff object is a ResizableDoubleArray with the same data and properties as this
    
    Since:
    
    2.0
  - hashCode
```
public int hashCode()
```
    Returns a hash code consistent with equals.
    
    Overrides:
    
    hashCode in class java.lang.Object
    
    Returns:
    
    the hash code representing this ResizableDoubleArray.
    
    Since:
    
    2.0

Class ResizableDoubleArray

Important note: Usage should not assume that this class is thread-safe even though some of the methods are synchronized. This qualifier will be dropped in the next major release (4.0).

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

ADDITIVE_MODE

MULTIPLICATIVE_MODE

serialVersionUID

DEFAULT_INITIAL_CAPACITY

DEFAULT_EXPANSION_FACTOR

DEFAULT_CONTRACTION_DELTA

contractionCriterion

expansionFactor

expansionMode

internalArray

numElements

startIndex

Constructor Detail

ResizableDoubleArray

ResizableDoubleArray

ResizableDoubleArray

ResizableDoubleArray

ResizableDoubleArray

ResizableDoubleArray

ResizableDoubleArray

ResizableDoubleArray

ResizableDoubleArray

ResizableDoubleArray

Method Detail

addElement

addElements

addElementRolling

substituteMostRecentElement

checkContractExpand

checkContractExpand

clear

contract

discardFrontElements

discardMostRecentElements

discardExtremeElements

expand

expandTo

getContractionCriteria

getContractionCriterion

getElement

getElements

getExpansionFactor

getExpansionMode

getInternalLength

getCapacity

getNumElements

getInternalValues

getArrayRef

getStartIndex

setContractionCriteria

compute

setElement

setExpansionFactor

setExpansionMode

setExpansionMode

setInitialCapacity

setNumElements

shouldContract

start

copy

copy

equals

hashCode

Important note: Usage should not assume that this class is thread-safe even though some of the methods are `synchronized`. This qualifier will be dropped in the next major release (4.0).