psteitz 2004/06/14 14:41:33
Modified: math/src/java/org/apache/commons/math/stat/univariate
DescriptiveStatisticsImpl.java
math/src/java/org/apache/commons/math/util DoubleArray.java
Added: math/src/java/org/apache/commons/math/util
ResizableDoubleArray.java
math/src/test/org/apache/commons/math/util
ResizableDoubleArrayTest.java
Removed: math/src/java/org/apache/commons/math/util
ContractableDoubleArray.java
ExpandableDoubleArray.java FixedDoubleArray.java
math/src/test/org/apache/commons/math/util
ContractableDoubleArrayTest.java
ExpandableDoubleArrayTest.java
FixedDoubleArrayTest.java
Log:
Combined Expandable, ContractableDoubleArrays into ResizableDoubleArray and dropped
FixedDoubleArray.
Revision Changes Path
1.7 +4 -4
jakarta-commons/math/src/java/org/apache/commons/math/stat/univariate/DescriptiveStatisticsImpl.java
Index: DescriptiveStatisticsImpl.java
===================================================================
RCS file:
/home/cvs/jakarta-commons/math/src/java/org/apache/commons/math/stat/univariate/DescriptiveStatisticsImpl.java,v
retrieving revision 1.6
retrieving revision 1.7
diff -u -r1.6 -r1.7
--- DescriptiveStatisticsImpl.java 1 Jun 2004 21:34:35 -0000 1.6
+++ DescriptiveStatisticsImpl.java 14 Jun 2004 21:41:33 -0000 1.7
@@ -17,7 +17,7 @@
import java.io.Serializable;
-import org.apache.commons.math.util.ContractableDoubleArray;
+import org.apache.commons.math.util.ResizableDoubleArray;
/**
* Default implementation of
@@ -36,7 +36,7 @@
/**
* Stored data values
*/
- protected ContractableDoubleArray eDA;
+ protected ResizableDoubleArray eDA;
/**
* Construct a DescriptiveStatisticsImpl with infinite window
@@ -51,7 +51,7 @@
*/
public DescriptiveStatisticsImpl(int window) {
super();
- eDA = new ContractableDoubleArray();
+ eDA = new ResizableDoubleArray();
setWindowSize(window);
}
1.12 +25 -18
jakarta-commons/math/src/java/org/apache/commons/math/util/DoubleArray.java
Index: DoubleArray.java
===================================================================
RCS file:
/home/cvs/jakarta-commons/math/src/java/org/apache/commons/math/util/DoubleArray.java,v
retrieving revision 1.11
retrieving revision 1.12
diff -u -r1.11 -r1.12
--- DoubleArray.java 8 Jun 2004 14:19:40 -0000 1.11
+++ DoubleArray.java 14 Jun 2004 21:41:33 -0000 1.12
@@ -17,10 +17,8 @@
/**
- * Provides a single interface for dealing with various flavors
- * of double arrays. This arrays framework follows the model of the
- * Collections API by allowing a user to select from a number of
- * array implementations with support for various storage mechanisms
+ * Provides a standard interface for double arrays. Allows different
+ * array implementations to support various storage mechanisms
* such as automatic expansion, contraction, and array "rolling".
*
* @version $Revision$ $Date$
@@ -29,7 +27,8 @@
/**
* Returns the number of elements currently in the array. Please note
- * that this is different from the length of the internal storage array.
+ * that this may be different from the length of the internal storage array.
+ *
* @return number of elements
*/
int getNumElements();
@@ -47,9 +46,11 @@
double getElement(int index);
/**
- * Sets the element at the specified index. This method may expand the
- * internal storage array to accomodate the insertion of a value at an
- * index beyond the current capacity.
+ * Sets the element at the specified index. If the specified index is greater
than
+ * <code>getNumElements() - 1</code>, the <code>numElements</code> property
+ * is increased to <code>index +1</code> 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).
*
* @param index index to store a value in
* @param value value to store at the specified index
@@ -66,23 +67,29 @@
void addElement(double value);
/**
- * Adds an element and moves the window of elements up one. This
- * has the effect of a FIFO. when you "roll" the array an element may be
- * removed from the array. In this case, the return value of this function is
the
- * discarded double. In some implementations, removal will only occur when
- * the array has reached a capacity threshold.
* <p>
- * When removal does occur, the effect is to add an element to the end of the
- * array and to discard the element at the beginning of the array.
+ * 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.
+ * </p>
+ * <p>
+ * 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.
+ * </p>
*
* @param value the value to be added to the array
* @return the value which has been discarded or "pushed" out of the array
- * by this rolling insert or null if no value has been discarded
+ * by this rolling insert
*/
double addElementRolling(double value);
/**
- * Returns a double[] of elements
+ * Returns a double[] array containing the elements of this
+ * <code>DoubleArray</code>. If the underlying implementation is
+ * array-based, this method should always return a copy, rather than a
+ * reference to the underlying array so that changes made to the returned
+ * array have no effect on the <code>DoubleArray.</code>
*
* @return all elements added to the array
*/
1.1
jakarta-commons/math/src/java/org/apache/commons/math/util/ResizableDoubleArray.java
Index: ResizableDoubleArray.java
===================================================================
/*
* Copyright 2003-2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.math.util;
import java.io.Serializable;
/**
* <p>
* A variable length [EMAIL PROTECTED] DoubleArray} implementation that
automatically
* handles expanding and contracting its internal storage array as elements
* are added and removed.
* </p>
* <p>
* The internal storage array starts with capacity determined by the
* <code>initialCapacity</code> property, which can be set by the constructor.
* The default initial capacity is 16. Adding elements using
* [EMAIL PROTECTED] #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
* <code>expansionMode</code> and <code>expansionFactor</code> properties.
* The <code>expansionMode</code> determines whether the size of the array is
* multiplied by the <code>expansionFactor</code> (MULTIPLICATIVE_MODE) or if
* the expansion is additive (ADDITIVE_MODE -- <code>expansionFactor</code>
* storage locations added). The default <code>expansionMode</code> is
* MULTIPLICATIVE_MODE and the default <code>expansionFactor</code>
* is 2.0.
* </p>
* <p>
* The [EMAIL PROTECTED] #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 [EMAIL PROTECTED] #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 <code>numElements</code> property) and if the difference
* is too large, the internal array is contracted to size
* <code>numElements + 1.</code> The determination of when the internal
* storage array is "too large" depends on the <code>expansionMode</code> and
* <code>contractionFactor</code> properties. If the <code>expansionMode</code>
* is <code>MULTIPLICATIVE_MODE</code>, contraction is triggered when the
* ratio between storage array length and <code>numElements</code> exceeds
* <code>contractionFactor.</code> If the <code>expansionMode</code>
* is <code>ADDITIVE_MODE,</code> the number of excess storage locations
* is compared to <code>contractionFactor.</code>
* </p>
* <p>
* To avoid cycles of expansions and contractions, the
* <code>expansionFactor</code> must not exceed the
* <code>contractionFactor.</code> Constructors and mutators for both of these
* properties enforce this requirement, throwing IllegalArgumentException if it
* is violated.
* </p>
* <p>
* @version $Revision: 1.1 $ $Date: 2004/06/14 21:41:33 $
*/
public class ResizableDoubleArray implements DoubleArray, Serializable {
/** Serializable version identifier */
static final long serialVersionUID = -3485529955529426875L;
/** additive expansion mode */
public static final int ADDITIVE_MODE = 1;
/** multiplicative expansion mode */
public static final int MULTIPLICATIVE_MODE = 0;
/**
* The contraction criteria determines when the internal array will be
* contracted to fit the number of elements contained in the element
* array + 1.
*/
protected float contractionCriteria = 2.5f;
/**
* The expansion factor of the array. When the array needs to be expanded,
* the new array size will be
* <code>internalArray.length * expansionFactor</code>
* if <code>expansionMode</code> is set to MULTIPLICATIVE_MODE, or
* <code>internalArray.length + expansionFactor</code> if
* <code>expansionMode</code> is set to ADDITIVE_MODE.
*/
protected float expansionFactor = 2.0f;
/**
* Determines whether array expansion by <code>expansionFactor</code>
* is additive or multiplicative.
*/
protected int expansionMode = MULTIPLICATIVE_MODE;
/**
* The initial capacity of the array. Initial capacity is not exposed as a
* property as it is only meaningful when passed to a constructor.
*/
protected int initialCapacity = 16;
/**
* The internal storage array.
*/
protected double[] internalArray;
/**
* The number of addressable elements in the array. Note that this
* has nothing to do with the length of the internal storage array.
*/
protected int numElements = 0;
/**
* The position of the first addressable element in the internal storage
* array. The addressable elements in the array are <code>
* internalArray[startIndex],...,internalArray[startIndex + numElements -1]
* </code>
*/
protected int startIndex = 0;
/**
* Create a ResizableArray with default properties.
* <ul>
* <li><code>initialCapacity = 16</code></li>
* <li><code>expansionMode = MULTIPLICATIVE_MODE</code></li>
* <li><code>expansionFactor = 2.5</code></li>
* <li><code>contractionFactor = 2.0</code></li>
* </ul>
*/
public ResizableDoubleArray() {
internalArray = new double[initialCapacity];
}
/**
* Create a ResizableArray with the specified initial capacity. Other
* properties take default values:
* <ul>
* <li><code>expansionMode = MULTIPLICATIVE_MODE</code></li>
* <li><code>expansionFactor = 2.5</code></li>
* <li><code>contractionFactor = 2.0</code></li>
* </ul>
* @param initialCapacity The initial size of the internal storage array
* @throws IllegalArgumentException if initialCapacity is not > 0
*/
public ResizableDoubleArray(int initialCapacity) {
setInitialCapacity(initialCapacity);
internalArray = new double[this.initialCapacity];
}
/**
* <p>
* Create a ResizableArray with the specified initial capacity
* and expansion factor. The remaining properties take default
* values:
* <ul>
* <li><code>expansionMode = MULTIPLICATIVE_MODE</code></li>
* <li><code>contractionFactor = 0.5 + expansionFactor</code></li>
* </ul></p>
* <p>
* Throws IllegalArgumentException if the following conditions are
* not met:
* <ul>
* <li><code>initialCapacity > 0</code></li>
* <li><code>expansionFactor > 1</code></li>
* </ul></p>
*
* @param initialCapacity The initial size of the internal storage array
* @param expansionFactor the array will be expanded based on this
* parameter
* @throws IllegalArgumentException if parameters are not valid
*/
public ResizableDoubleArray(int initialCapacity, float expansionFactor) {
this.expansionFactor = expansionFactor;
setInitialCapacity(initialCapacity);
internalArray = new double[initialCapacity];
setContractionCriteria(expansionFactor +0.5f);
}
/**
* <p>
* Create a ResizableArray with the specified initialCapacity,
* expansionFactor, and contractionCriteria. The <code>expansionMode</code>
* will default to <code>MULTIPLICATIVE_MODE.</code></p>
* <p>
* Throws IllegalArgumentException if the following conditions are
* not met:
* <ul>
* <li><code>initialCapacity > 0</code></li>
* <li><code>expansionFactor > 1</code></li>
* <li><code>contractionFactor >= expansionFactor</code></li>
* </ul></p>
* @param initialCapacity The initial size of the internal storage array
* @param expansionFactor the array will be expanded based on this
* parameter
* @param contractionCriteria The contraction Criteria.
* @throws IllegalArgumentException if parameters are not valid
*/
public ResizableDoubleArray(int initialCapacity, float expansionFactor,
float contractionCriteria) {
this.expansionFactor = expansionFactor;
setContractionCriteria(contractionCriteria);
setInitialCapacity(initialCapacity);
internalArray = new double[initialCapacity];
}
/**
* <p>
* Create a ResizableArray with the specified properties.</p>
* <p>
* Throws IllegalArgumentException if the following conditions are
* not met:
* <ul>
* <li><code>initialCapacity > 0</code></li>
* <li><code>expansionFactor > 1</code></li>
* <li><code>contractionFactor >= expansionFactor</code></li>
* <li><code>expansionMode in {MULTIPLICATIVE_MODE, ADDITIVE_MODE}</code>
* </li>
* </ul></p>
*
* @param initialCapacity the initial size of the internal storage array
* @param expansionFactor the array will be expanded based on this
* parameter
* @param contractionCriteria the contraction Criteria
* @param expansionMode the expansion mode
* @throws IllegalArgumentException if parameters are not valid
*/
public ResizableDoubleArray(int initialCapacity, float expansionFactor,
float contractionCriteria, int expansionMode) {
this.expansionFactor = expansionFactor;
setContractionCriteria(contractionCriteria);
setInitialCapacity(initialCapacity);
setExpansionMode(expansionMode);
internalArray = new double[initialCapacity];
}
/**
* Adds an element to the end of this expandable array.
*
* @param value to be added to end of array
*/
public synchronized void addElement(double value) {
numElements++;
if ((startIndex + numElements) > internalArray.length) {
expand();
}
internalArray[startIndex + (numElements - 1)] = value;
if (shouldContract()) {
contract();
}
}
/**
* <p>
* 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.
* </p>
* <p>
* 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.
* </p>
*
* @param value the value to be added to the array
* @return the value which has been discarded or "pushed" out of the array
* by this rolling insert
*/
public synchronized double addElementRolling(double value) {
double discarded = internalArray[startIndex];
if ((startIndex + (numElements + 1)) > internalArray.length) {
expand();
}
// Increment the start index
startIndex += 1;
// Add the new value
internalArray[startIndex + (numElements - 1)] = value;
// Check the contraction criteria
if (shouldContract()) {
contract();
}
return discarded;
}
/**
* Checks the expansion factor and the contraction criteria and throws an
* IllegalArgumentException if the contractionCriteria is less than the
* expansionCriteria
*
* @param expansionFactor factor to be checked
* @param contractionCritera critera to be checked
* @throws IllegalArgumentException if the contractionCriteria is less than
* the expansionCriteria.
*/
protected void checkContractExpand(
float contractionCritera,
float expansionFactor) {
if (contractionCritera < expansionFactor) {
String msg =
"Contraction criteria can never be smaller than " +
"the expansion factor. This would lead to a never " +
"ending loop of expansion and contraction as a newly " +
"expanded internal storage array would immediately " +
"satisfy the criteria for contraction";
throw new IllegalArgumentException(msg);
}
if (contractionCriteria <= 1.0) {
String msg =
"The contraction criteria must be a number larger " +
"than one. If the contractionCriteria is less than or " +
"equal to one an endless loop of contraction and " +
"expansion would ensue as an internalArray.length " +
"== numElements would satisfy the contraction criteria";
throw new IllegalArgumentException(msg);
}
if (expansionFactor <= 1.0) {
String msg =
"The expansion factor must be a number greater than 1.0";
throw new IllegalArgumentException(msg);
}
}
/**
* Clear the array, reset the size to the initialCapacity and the number
* of elements to zero.
*/
public synchronized void clear() {
numElements = 0;
internalArray = new double[initialCapacity];
}
/**
* 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.
*/
public synchronized void contract() {
double[] tempArray = new double[numElements + 1];
// Copy and swap - copy only the element array from the src array.
System.arraycopy(internalArray, startIndex, tempArray, 0, numElements);
internalArray = tempArray;
// Reset the start index to zero
startIndex = 0;
}
/**
* Discards the <code>i<code> initial elements of the array. For example,
* if the array contains the elements 1,2,3,4, invoking
* <code>discardFrontElements(2)</code> will cause the first two elements
* to be discarded, leaving 3,4 in the array. Throws illegalArgumentException
* if i exceeds numElements.
*
* @param i the number of elements to discard from the front of the array
* @throws IllegalArgumentException if i is greater than numElements.
*/
public synchronized void discardFrontElements(int i) {
if (i > numElements) {
String msg = "Cannot discard more elements than are" +
"contained in this array.";
throw new IllegalArgumentException(msg);
} else if (i < 0) {
String msg = "Cannot discard a negative number of elements.";
throw new IllegalArgumentException(msg);
} else {
// "Subtract" this number of discarded from numElements
numElements -= i;
startIndex += i;
}
if (shouldContract()) {
contract();
}
}
/**
* Expands the internal storage array using the expansion factor.
* <p>
* if <code>expansionMode</code> is set to MULTIPLICATIVE_MODE,
* the new array size will be <code>internalArray.length *
expansionFactor.</code>
* If <code>expansionMode</code> is set to ADDITIVE_MODE, the length
* after expansion will be <code>internalArray.length + expansionFactor</code>
*/
protected synchronized void expand() {
// notice the use of Math.ceil(), this gaurantees that we will always
// have an array of at least currentSize + 1. Assume that the
// current initial capacity is 1 and the expansion factor
// is 1.000000000000000001. The newly calculated size will be
// rounded up to 2 after the multiplication is performed.
int newSize = 0;
if (expansionMode == MULTIPLICATIVE_MODE) {
newSize = (int) Math.ceil(internalArray.length * expansionFactor);
} else {
newSize = internalArray.length + Math.round(expansionFactor);
}
double[] tempArray = new double[newSize];
// Copy and swap
System.arraycopy(internalArray, 0, tempArray, 0, internalArray.length);
internalArray = tempArray;
}
/**
* Expands the internal storage array to the specified size.
*
* @param size Size of the new internal storage array
*/
private synchronized void expandTo(int size) {
double[] tempArray = new double[size];
// Copy and swap
System.arraycopy(internalArray, 0, tempArray, 0, internalArray.length);
internalArray = tempArray;
}
/**
* The contraction criteria defines when the internal array will contract
* to store only the number of elements in the element array.
* If the <code>expansionMode</code> is <code>MULTIPLICATIVE_MODE</code>,
* contraction is triggered when the ratio between storage array length
* and <code>numElements</code> exceeds <code>contractionFactor</code>.
* If the <code>expansionMode</code> is <code>ADDITIVE_MODE</code>, the
* number of excess storage locations is compared to
* <code>contractionFactor.</code>
*
* @return the contraction criteria used to reclaim memory.
*/
public float getContractionCriteria() {
return contractionCriteria;
}
/**
* Returns the element at the specified index
*
* @param index index to fetch a value from
* @return value stored at the specified index
* @throws ArrayIndexOutOfBoundsException if <code>index</code> is less than
* zero or is greater than <code>getNumElements() - 1</code>.
*/
public double getElement(int index) {
double value = Double.NaN;
if (index >= numElements) {
String msg =
"The index specified: " + index +
" is larger than the current number of elements";
throw new ArrayIndexOutOfBoundsException(msg);
} else if (index >= 0) {
value = internalArray[startIndex + index];
} else {
String msg =
"Elements cannot be retrieved from a negative array index";
throw new ArrayIndexOutOfBoundsException(msg);
}
return value;
}
/**
* Returns a double[] array containing the elements of this
* <code>ResizableArray</code>. 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 <code>ResizableArray.</code>
*/
public double[] getElements() {
double[] elementArray = new double[numElements];
System.arraycopy( internalArray, startIndex, elementArray, 0,
numElements);
return elementArray;
}
/**
* The expansion factor controls the size of a new aray when an array
* needs to be expanded. The <code>expansionMode</code>
* determines whether the size of the array is multiplied by the
* <code>expansionFactor</code> (MULTIPLICATIVE_MODE) or if
* the expansion is additive (ADDITIVE_MODE -- <code>expansionFactor</code>
* storage locations added). The default <code>expansionMode</code> is
* MULTIPLICATIVE_MODE and the default <code>expansionFactor</code>
* is 2.0.
*
* @return the expansion factor of this expandable double array
*/
public float getExpansionFactor() {
return expansionFactor;
}
/**
* The <code>expansionMode</code> determines whether the internal storage
* array grows additively (ADDITIVE_MODE) or multiplicatively
* (MULTIPLICATIVE_MODE) when it is expanded.
*
* @return Returns the expansionMode.
*/
public int getExpansionMode() {
return expansionMode;
}
/**
* 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.
*
* @return the length of the internal storage array.
*/
int getInternalLength() {
return (internalArray.length);
}
/**
* Returns the number of elements currently in the array. Please note
* that this is different from the length of the internal storage array.
*
* @return number of elements
*/
public int getNumElements() {
return (numElements);
}
/**
* 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 <code>startIndex</code> is
* required (available via the [EMAIL PROTECTED] #start} method). This method
should
* only be used in cases where copying the internal array is not practical.
* The [EMAIL PROTECTED] #getElements} method should be used in all other cases.
*
*
* @return the internal storage array used by this object
*/
public double[] getValues() {
return (internalArray);
}
/**
* Sets the contraction criteria for this ExpandContractDoubleArray.
*
* @param contractionCriteria contraction criteria
*/
public void setContractionCriteria(float contractionCriteria) {
checkContractExpand(contractionCriteria, getExpansionFactor());
this.contractionCriteria = contractionCriteria;
}
/**
* Sets the element at the specified index. If the specified index is greater
than
* <code>getNumElements() - 1</code>, the <code>numElements</code> property
* is increased to <code>index +1</code> 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).
*
* @param index index to store a value in
* @param value value to store at the specified index
* @throws ArrayIndexOutOfBoundsException if <code>index</code> is less than
* zero.
*/
public synchronized void setElement(int index, double value) {
if (index < 0) {
String msg = "Cannot set an element at a negative index";
throw new ArrayIndexOutOfBoundsException(msg);
}
if (index + 1 > numElements) {
numElements = index + 1;
}
if ((startIndex + index) >= internalArray.length) {
expandTo(startIndex + (index + 1));
}
internalArray[startIndex + index] = value;
}
/**
* Sets the expansionFactor. Throws IllegalArgumentException if the
* the following conditions are not met:
* <ul>
* <li><code>expansionFactor > 1</code></li>
* <li><code>contractionFactor >= expansionFactor</code></li>
* </ul>
*
* @throws IllegalArgumentException if expansionFactor is <= 1 or greater
* than contractionFactor
*/
public void setExpansionFactor(float expansionFactor) {
checkContractExpand(getContractionCriteria(), expansionFactor);
// The check above verifies that the expansion factor is > 1.0;
this.expansionFactor = expansionFactor;
}
/**
* Sets the <code>expansionMode</code>. The specified value must be one of
* ADDITIVE_MODE, MULTIPLICATIVE_MODE.
*
* @param expansionMode The expansionMode to set.
* @throws IllegalArgumentException if the specified mode value is not valid
*/
public void setExpansionMode(int expansionMode) {
if (expansionMode != MULTIPLICATIVE_MODE &&
expansionMode != ADDITIVE_MODE) {
throw new IllegalArgumentException("Illegal expansionMode setting.");
}
this.expansionMode = expansionMode;
}
/**
* Sets the initial capacity. Should only be invoked by constructors.
*
* @param initialCapacity of the array
* @throws IllegalArgumentException if <code>initialCapacity</code> is not
* positive.
*/
protected void setInitialCapacity(int initialCapacity) {
if (initialCapacity > 0) {
this.initialCapacity = initialCapacity;
} else {
String msg =
"The initial capacity supplied: " + initialCapacity +
"must be a positive integer";
throw new IllegalArgumentException(msg);
}
}
/**
* 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.
*
* @param i a new number of elements
* @throws IllegalArgumentException if <code>i</code> is negative.
*/
public synchronized void setNumElements(int i) {
// If index is negative thrown an error
if (i < 0) {
String msg =
"Number of elements must be zero or a positive " + "integer";
throw new IllegalArgumentException(msg);
}
// Test the new num elements, check to see if the array needs to be
// expanded to accomodate this new number of elements
if ((startIndex + i) > internalArray.length) {
expandTo(startIndex + i);
}
// Set the new number of elements to new value
numElements = i;
}
/**
* Returns true if the internal storage array has too many unused
* storage positions.
*
* @return true if array satisfies the contraction criteria
*/
private synchronized boolean shouldContract() {
if (expansionMode == MULTIPLICATIVE_MODE) {
return (internalArray.length / numElements) > contractionCriteria;
} else {
return (internalArray.length - numElements) > contractionCriteria;
}
}
/**
* 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 <code>
* internalArray[startIndex],...,internalArray[startIndex + numElements -1]
* </code>
*
* @return starting index
*/
public int start() {
return startIndex;
}
}
1.1
jakarta-commons/math/src/test/org/apache/commons/math/util/ResizableDoubleArrayTest.java
Index: ResizableDoubleArrayTest.java
===================================================================
/*
* Copyright 2003-2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.math.util;
import org.apache.commons.math.random.RandomDataImpl;
import org.apache.commons.math.random.RandomData;
/**
* This class contains test cases for the ResizableDoubleArray.
*
* @version $Revision: 1.1 $ $Date: 2004/06/14 21:41:33 $
*/
public class ResizableDoubleArrayTest extends DoubleArrayAbstractTest {
public ResizableDoubleArrayTest(String name) {
super( name );
}
protected void tearDown() throws Exception {
da = null;
ra = null;
}
protected void setUp() throws Exception {
da = new ResizableDoubleArray();
ra = new ResizableDoubleArray();
}
public void testConstructors() {
float defaultExpansionFactor = 2.0f;
float defaultContractionCriteria = 2.5f;
int defaultMode = ResizableDoubleArray.MULTIPLICATIVE_MODE;
ResizableDoubleArray testDa = new ResizableDoubleArray(2);
assertEquals(0, testDa.getNumElements());
assertEquals(2, testDa.getInternalLength());
assertEquals(defaultExpansionFactor, testDa.getExpansionFactor(), 0);
assertEquals(defaultContractionCriteria, testDa.getContractionCriteria(), 0);
assertEquals(defaultMode, testDa.getExpansionMode());
try {
da = new ResizableDoubleArray(-1);
fail("Expecting IllegalArgumentException");
} catch (IllegalArgumentException ex) {
// expected
}
testDa = new ResizableDoubleArray(2, 2.0f);
assertEquals(0, testDa.getNumElements());
assertEquals(2, testDa.getInternalLength());
assertEquals(defaultExpansionFactor, testDa.getExpansionFactor(), 0);
assertEquals(defaultContractionCriteria, testDa.getContractionCriteria(), 0);
assertEquals(defaultMode, testDa.getExpansionMode());
try {
da = new ResizableDoubleArray(2, 0.5f);
fail("Expecting IllegalArgumentException");
} catch (IllegalArgumentException ex) {
// expected
}
testDa = new ResizableDoubleArray(2, 3.0f);
assertEquals(3.0f, testDa.getExpansionFactor(), 0);
assertEquals(3.5f, testDa.getContractionCriteria(), 0);
testDa = new ResizableDoubleArray(2, 2.0f, 3.0f);
assertEquals(0, testDa.getNumElements());
assertEquals(2, testDa.getInternalLength());
assertEquals(defaultExpansionFactor, testDa.getExpansionFactor(), 0);
assertEquals(3.0f, testDa.getContractionCriteria(), 0);
assertEquals(defaultMode, testDa.getExpansionMode());
try {
da = new ResizableDoubleArray(2, 2.0f, 1.5f);
fail("Expecting IllegalArgumentException");
} catch (IllegalArgumentException ex) {
// expected
}
testDa = new ResizableDoubleArray(2, 2.0f, 3.0f,
ResizableDoubleArray.ADDITIVE_MODE);
assertEquals(0, testDa.getNumElements());
assertEquals(2, testDa.getInternalLength());
assertEquals(defaultExpansionFactor, testDa.getExpansionFactor(), 0);
assertEquals(3.0f, testDa.getContractionCriteria(), 0);
assertEquals(ResizableDoubleArray.ADDITIVE_MODE,
testDa.getExpansionMode());
try {
da = new ResizableDoubleArray(2, 2.0f, 2.5f, -1);
fail("Expecting IllegalArgumentException");
} catch (IllegalArgumentException ex) {
// expected
}
}
public void testSetElementArbitraryExpansion() {
// MULTIPLICATIVE_MODE
da.addElement(2.0);
da.addElement(4.0);
da.addElement(6.0);
da.setElement(1, 3.0);
// Expand the array arbitrarily to 1000 items
da.setElement(1000, 3.4);
assertEquals( "The number of elements should now be 1001, it isn't",
da.getNumElements(), 1001);
assertEquals( "Uninitialized Elements are default value of 0.0, index 766
wasn't", 0.0,
da.getElement( 760 ), Double.MIN_VALUE );
assertEquals( "The 1000th index should be 3.4, it isn't", 3.4,
da.getElement(1000),
Double.MIN_VALUE );
assertEquals( "The 0th index should be 2.0, it isn't", 2.0,
da.getElement(0),
Double.MIN_VALUE);
// Make sure numElements and expansion work correctly for expansion boundary
cases
da.clear();
da.addElement(2.0);
da.addElement(4.0);
da.addElement(6.0);
assertEquals(4, ((ResizableDoubleArray) da).getInternalLength());
assertEquals(3, da.getNumElements());
da.setElement(3, 7.0);
assertEquals(4, ((ResizableDoubleArray) da).getInternalLength());
assertEquals(4, da.getNumElements());
da.setElement(10, 10.0);
assertEquals(11, ((ResizableDoubleArray) da).getInternalLength());
assertEquals(11, da.getNumElements());
da.setElement(9, 10.0);
assertEquals(11, ((ResizableDoubleArray) da).getInternalLength());
assertEquals(11, da.getNumElements());
try {
da.setElement(-2, 3);
fail("Expecting ArrayIndexOutOfBoundsException for negative index");
} catch (ArrayIndexOutOfBoundsException ex) {
// expected
}
// ADDITIVE_MODE
ResizableDoubleArray testDa = new ResizableDoubleArray(2, 2.0f, 3.0f,
ResizableDoubleArray.ADDITIVE_MODE);
assertEquals(2, testDa.getInternalLength());
testDa.addElement(1d);
testDa.addElement(1d);
assertEquals(2, testDa.getInternalLength());
testDa.addElement(1d);
assertEquals(4, testDa.getInternalLength());
}
public void testAdd1000() {
super.testAdd1000();
assertEquals("Internal Storage length should be 1024 if we started out with
initial capacity of " +
"16 and an expansion factor of 2.0",
1024, ((ResizableDoubleArray) da).getInternalLength());
}
public void testAddElementRolling() {
super.testAddElementRolling();
// MULTIPLICATIVE_MODE
da.clear();
da.addElement(1);
da.addElement(2);
da.addElementRolling(3);
assertEquals(3, da.getElement(1), 0);
da.addElementRolling(4);
assertEquals(3, da.getElement(0), 0);
assertEquals(4, da.getElement(1), 0);
da.addElement(5);
assertEquals(5, da.getElement(2), 0);
da.addElementRolling(6);
assertEquals(4, da.getElement(0), 0);
assertEquals(5, da.getElement(1), 0);
assertEquals(6, da.getElement(2), 0);
// ADDITIVE_MODE (x's are occupied storage locations, 0's are open)
ResizableDoubleArray testDa = new ResizableDoubleArray(2, 2.0f, 2.5f,
ResizableDoubleArray.ADDITIVE_MODE);
assertEquals(2, testDa.getInternalLength());
testDa.addElement(1d); // x,0
testDa.addElement(2d); // x,x
testDa.addElement(3d); // x,x,x,0 -- expanded
assertEquals(1d, testDa.getElement(0), 0);
assertEquals(2d, testDa.getElement(1), 0);
assertEquals(3d, testDa.getElement(2), 0);
assertEquals(4, testDa.getInternalLength()); // x,x,x,0
assertEquals(3, testDa.getNumElements());
testDa.addElementRolling(4d);
assertEquals(2d, testDa.getElement(0), 0);
assertEquals(3d, testDa.getElement(1), 0);
assertEquals(4d, testDa.getElement(2), 0);
assertEquals(4, testDa.getInternalLength()); // 0,x,x,x
assertEquals(3, testDa.getNumElements());
testDa.addElementRolling(5d); // 0,0,x,x,x,0 -- time to contract
assertEquals(3d, testDa.getElement(0), 0);
assertEquals(4d, testDa.getElement(1), 0);
assertEquals(5d, testDa.getElement(2), 0);
assertEquals(4, testDa.getInternalLength()); // contracted -- x,x,x,0
assertEquals(3, testDa.getNumElements());
try {
testDa.getElement(4);
fail("Expecting ArrayIndexOutOfBoundsException");
} catch (ArrayIndexOutOfBoundsException ex) {
// expected
}
try {
testDa.getElement(-1);
fail("Expecting ArrayIndexOutOfBoundsException");
} catch (ArrayIndexOutOfBoundsException ex) {
// expected
}
}
public void testSetNumberOfElements() {
da.addElement( 1.0 );
da.addElement( 1.0 );
da.addElement( 1.0 );
da.addElement( 1.0 );
da.addElement( 1.0 );
da.addElement( 1.0 );
assertEquals( "Number of elements should equal 6", da.getNumElements(), 6);
((ResizableDoubleArray) da).setNumElements( 3 );
assertEquals( "Number of elements should equal 3", da.getNumElements(), 3);
try {
((ResizableDoubleArray) da).setNumElements( -3 );
fail( "Setting number of elements to negative should've thrown an
exception");
} catch( IllegalArgumentException iae ) {
}
((ResizableDoubleArray) da).setNumElements(1024);
assertEquals( "Number of elements should now be 1024", da.getNumElements(),
1024);
assertEquals( "Element 453 should be a default double", da.getElement( 453
), 0.0, Double.MIN_VALUE);
}
public void testWithInitialCapacity() {
ResizableDoubleArray eDA2 = new ResizableDoubleArray(2);
assertEquals("Initial number of elements should be 0", 0,
eDA2.getNumElements());
RandomData randomData = new RandomDataImpl();
int iterations = randomData.nextInt(100, 1000);
for( int i = 0; i < iterations; i++) {
eDA2.addElement( i );
}
assertEquals("Number of elements should be equal to " + iterations,
iterations, eDA2.getNumElements());
eDA2.addElement( 2.0 );
assertEquals("Number of elements should be equals to " + (iterations +1),
iterations + 1 , eDA2.getNumElements() );
}
public void testWithInitialCapacityAndExpansionFactor() {
ResizableDoubleArray eDA3 = new ResizableDoubleArray(3, 3.0f, 3.5f);
assertEquals("Initial number of elements should be 0", 0,
eDA3.getNumElements() );
RandomData randomData = new RandomDataImpl();
int iterations = randomData.nextInt(100, 3000);
for( int i = 0; i < iterations; i++) {
eDA3.addElement( i );
}
assertEquals("Number of elements should be equal to " + iterations,
iterations,eDA3.getNumElements());
eDA3.addElement( 2.0 );
assertEquals("Number of elements should be equals to " + (iterations +1),
iterations +1, eDA3.getNumElements() );
assertEquals("Expansion factor should equal 3.0", 3.0f,
eDA3.getExpansionFactor(), Double.MIN_VALUE);
}
public void testDiscard() {
da.addElement(2.0);
da.addElement(2.0);
da.addElement(2.0);
da.addElement(2.0);
da.addElement(2.0);
da.addElement(2.0);
da.addElement(2.0);
da.addElement(2.0);
da.addElement(2.0);
da.addElement(2.0);
da.addElement(2.0);
assertEquals( "Number of elements should be 11", 11, da.getNumElements());
((ResizableDoubleArray)da).discardFrontElements(5);
assertEquals( "Number of elements should be 6", 6, da.getNumElements());
try {
((ResizableDoubleArray)da).discardFrontElements(-1);
fail( "Trying to discard a negative number of element is not allowed");
} catch( Exception e ){
}
try {
((ResizableDoubleArray)da).discardFrontElements( 10000 );
fail( "You can't discard more elements than the array contains");
} catch( Exception e ){
}
}
public void testMutators() {
((ResizableDoubleArray)da).setContractionCriteria(10f);
assertEquals(10f, ((ResizableDoubleArray)da).getContractionCriteria(), 0);
((ResizableDoubleArray)da).setExpansionFactor(8f);
assertEquals(8f, ((ResizableDoubleArray)da).getExpansionFactor(), 0);
try {
((ResizableDoubleArray)da).setExpansionFactor(11f); // greater than
contractionCriteria
fail("Expecting IllegalArgumentException");
} catch (IllegalArgumentException ex) {
// expected
}
((ResizableDoubleArray)da).setExpansionMode(
ResizableDoubleArray.ADDITIVE_MODE);
assertEquals(ResizableDoubleArray.ADDITIVE_MODE,
((ResizableDoubleArray)da).getExpansionMode());
try {
((ResizableDoubleArray)da).setExpansionMode(-1);
fail ("Expecting IllegalArgumentException");
} catch (IllegalArgumentException ex) {
// expected
}
}
}
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