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The Math project is a library of lightweight, self-contained mathematics and statistics components addressing the most common practical problems not immediately available in the Java programming language or commons-lang.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.linear;
import java.io.Serializable;
import java.lang.reflect.Array;
import org.apache.commons.math.Field;
import org.apache.commons.math.FieldElement;
import org.apache.commons.math.MathRuntimeException;
import org.apache.commons.math.util.OpenIntToFieldHashMap;
/**
* This class implements the {@link FieldVector} interface with a {@link OpenIntToFieldHashMap} backing store.
* @param the type of the field elements
* @version $Revision: 799857 $ $Date: 2009-08-01 09:07:12 -0400 (Sat, 01 Aug 2009) $
* @since 2.0
*/
public class SparseFieldVector> implements FieldVector, Serializable {
/**
* Serial version id
*/
private static final long serialVersionUID = 7841233292190413362L;
/** Field to which the elements belong. */
private final Field field;
/** Entries of the vector. */
private final OpenIntToFieldHashMap entries;
/** Dimension of the vector. */
private final int virtualSize;
/**
* Build a 0-length vector.
* Zero-length vectors may be used to initialize construction of vectors
* by data gathering. We start with zero-length and use either the {@link
* #SparseFieldVector(SparseFieldVector, int)} constructor
* or one of the append method ({@link #append(FieldElement)},
* {@link #append(FieldElement[])}, {@link #append(FieldVector)},
* {@link #append(SparseFieldVector)}) to gather data into this vector.
* @param field field to which the elements belong
*/
public SparseFieldVector(Field field) {
this(field, 0);
}
/**
* Construct a (dimension)-length vector of zeros.
* @param field field to which the elements belong
* @param dimension Size of the vector
*/
public SparseFieldVector(Field field, int dimension) {
this.field = field;
virtualSize = dimension;
entries = new OpenIntToFieldHashMap(field);
}
/**
* Build a resized vector, for use with append.
* @param v The original vector
* @param resize The amount to resize it
*/
protected SparseFieldVector(SparseFieldVector v, int resize) {
field = v.field;
virtualSize = v.getDimension() + resize;
entries = new OpenIntToFieldHashMap(v.entries);
}
/**
* Build a vector with known the sparseness (for advanced use only).
* @param field field to which the elements belong
* @param dimension The size of the vector
* @param expectedSize The expected number of non-zero entries
*/
public SparseFieldVector(Field field, int dimension, int expectedSize) {
this.field = field;
virtualSize = dimension;
entries = new OpenIntToFieldHashMap(field,expectedSize);
}
/**
* Create from a Field array.
* Only non-zero entries will be stored
* @param field field to which the elements belong
* @param values The set of values to create from
*/
public SparseFieldVector(Field field, T[] values) {
this.field = field;
virtualSize = values.length;
entries = new OpenIntToFieldHashMap(field);
for (int key = 0; key < values.length; key++) {
T value = values[key];
entries.put(key, value);
}
}
/**
* Copy constructor.
* @param v The instance to copy from
*/
public SparseFieldVector(SparseFieldVector v) {
field = v.field;
virtualSize = v.getDimension();
entries = new OpenIntToFieldHashMap(v.getEntries());
}
/**
* Get the entries of this instance.
* @return entries of this instance
*/
private OpenIntToFieldHashMap getEntries() {
return entries;
}
/**
* Optimized method to add sparse vectors.
* @param v vector to add
* @return The sum of this and v
* @throws IllegalArgumentException If the dimensions don't match
*/
public FieldVector add(SparseFieldVector v) throws IllegalArgumentException {
checkVectorDimensions(v.getDimension());
SparseFieldVector res = (SparseFieldVector)copy();
OpenIntToFieldHashMap.Iterator iter = v.getEntries().iterator();
while (iter.hasNext()) {
iter.advance();
int key = iter.key();
T value = iter.value();
if (entries.containsKey(key)) {
res.setEntry(key, entries.get(key).add(value));
} else {
res.setEntry(key, value);
}
}
return res;
}
/** {@inheritDoc} */
public FieldVector add(T[] v) throws IllegalArgumentException {
checkVectorDimensions(v.length);
SparseFieldVector res = new SparseFieldVector(field,getDimension());
for (int i = 0; i < v.length; i++) {
res.setEntry(i, v[i].add(getEntry(i)));
}
return res;
}
/**
* Construct a vector by appending a vector to this vector.
* @param v vector to append to this one.
* @return a new vector
*/
public FieldVector append(SparseFieldVector v) {
SparseFieldVector res = new SparseFieldVector(this, v.getDimension());
OpenIntToFieldHashMap.Iterator iter = v.entries.iterator();
while (iter.hasNext()) {
iter.advance();
res.setEntry(iter.key() + virtualSize, iter.value());
}
return res;
}
/** {@inheritDoc} */
public FieldVector append(FieldVector v) {
if (v instanceof SparseFieldVector) {
return append((SparseFieldVector) v);
} else {
return append(v.toArray());
}
}
/** {@inheritDoc} */
public FieldVector append(T d) {
FieldVector res = new SparseFieldVector(this, 1);
res.setEntry(virtualSize, d);
return res;
}
/** {@inheritDoc} */
public FieldVector append(T[] a) {
FieldVector res = new SparseFieldVector(this, a.length);
for (int i = 0; i < a.length; i++) {
res.setEntry(i + virtualSize, a[i]);
}
return res;
}
/** {@inheritDoc} */
public FieldVector copy() {
return new SparseFieldVector(this);
}
/** {@inheritDoc} */
public T dotProduct(FieldVector v) throws IllegalArgumentException {
checkVectorDimensions(v.getDimension());
T res = field.getZero();
OpenIntToFieldHashMap.Iterator iter = entries.iterator();
while (iter.hasNext()) {
iter.advance();
res = res.add(v.getEntry(iter.key()).multiply(iter.value()));
}
return res;
}
/** {@inheritDoc} */
public T dotProduct(T[] v) throws IllegalArgumentException {
checkVectorDimensions(v.length);
T res = field.getZero();
OpenIntToFieldHashMap.Iterator iter = entries.iterator();
while (iter.hasNext()) {
int idx = iter.key();
T value = field.getZero();
if (idx < v.length) {
value = v[idx];
}
res = res.add(value.multiply(iter.value()));
}
return res;
}
/** {@inheritDoc} */
public FieldVector ebeDivide(FieldVector v)
throws IllegalArgumentException {
checkVectorDimensions(v.getDimension());
SparseFieldVector res = new SparseFieldVector(this);
OpenIntToFieldHashMap.Iterator iter = res.entries.iterator();
while (iter.hasNext()) {
iter.advance();
res.setEntry(iter.key(), iter.value().divide(v.getEntry(iter.key())));
}
return res;
}
/** {@inheritDoc} */
public FieldVector ebeDivide(T[] v) throws IllegalArgumentException {
checkVectorDimensions(v.length);
SparseFieldVector res = new SparseFieldVector(this);
OpenIntToFieldHashMap.Iterator iter = res.entries.iterator();
while (iter.hasNext()) {
iter.advance();
res.setEntry(iter.key(), iter.value().divide(v[iter.key()]));
}
return res;
}
/** {@inheritDoc} */
public FieldVector ebeMultiply(FieldVector v)throws IllegalArgumentException {
checkVectorDimensions(v.getDimension());
SparseFieldVector res = new SparseFieldVector(this);
OpenIntToFieldHashMap.Iterator iter = res.entries.iterator();
while (iter.hasNext()) {
iter.advance();
res.setEntry(iter.key(), iter.value().multiply(v.getEntry(iter.key())));
}
return res;
}
/** {@inheritDoc} */
public FieldVector ebeMultiply(T[] v) throws IllegalArgumentException {
checkVectorDimensions(v.length);
SparseFieldVector res = new SparseFieldVector(this);
OpenIntToFieldHashMap.Iterator iter = res.entries.iterator();
while (iter.hasNext()) {
iter.advance();
res.setEntry(iter.key(), iter.value().multiply(v[iter.key()]));
}
return res;
}
/** {@inheritDoc} */
public T[] getData() {
T[] res = buildArray(virtualSize);
OpenIntToFieldHashMap.Iterator iter = entries.iterator();
while (iter.hasNext()) {
iter.advance();
res[iter.key()] = iter.value();
}
return res;
}
/** {@inheritDoc} */
public int getDimension() {
return virtualSize;
}
/** {@inheritDoc} */
public T getEntry(int index) throws MatrixIndexException {
checkIndex(index);
return entries.get(index);
}
/** {@inheritDoc} */
public Field getField() {
return field;
}
/** {@inheritDoc} */
public FieldVector getSubVector(int index, int n)
throws MatrixIndexException {
checkIndex(index);
checkIndex(index + n - 1);
SparseFieldVector res = new SparseFieldVector(field,n);
int end = index + n;
OpenIntToFieldHashMap.Iterator iter = entries.iterator();
while (iter.hasNext()) {
iter.advance();
int key = iter.key();
if (key >= index && key < end) {
res.setEntry(key - index, iter.value());
}
}
return res;
}
/** {@inheritDoc} */
public FieldVector mapAdd(T d) {
return copy().mapAddToSelf(d);
}
/** {@inheritDoc} */
public FieldVector mapAddToSelf(T d) {
for (int i = 0; i < virtualSize; i++) {
setEntry(i, getEntry(i).add(d));
}
return this;
}
/** {@inheritDoc} */
public FieldVector mapDivide(T d) {
return copy().mapDivideToSelf(d);
}
/** {@inheritDoc} */
public FieldVector mapDivideToSelf(T d) {
OpenIntToFieldHashMap.Iterator iter = entries.iterator();
while (iter.hasNext()) {
iter.advance();
entries.put(iter.key(), iter.value().divide(d));
}
return this;
}
/** {@inheritDoc} */
public FieldVector mapInv() {
return copy().mapInvToSelf();
}
/** {@inheritDoc} */
public FieldVector mapInvToSelf() {
for (int i = 0; i < virtualSize; i++) {
setEntry(i, field.getOne().divide(getEntry(i)));
}
return this;
}
/** {@inheritDoc} */
public FieldVector mapMultiply(T d) {
return copy().mapMultiplyToSelf(d);
}
/** {@inheritDoc} */
public FieldVector mapMultiplyToSelf(T d) {
OpenIntToFieldHashMap.Iterator iter = entries.iterator();
while (iter.hasNext()) {
iter.advance();
entries.put(iter.key(), iter.value().multiply(d));
}
return this;
}
/** {@inheritDoc} */
public FieldVector mapSubtract(T d) {
return copy().mapSubtractToSelf(d);
}
/** {@inheritDoc} */
public FieldVector mapSubtractToSelf(T d) {
return mapAddToSelf(field.getZero().subtract(d));
}
/**
* Optimized method to compute outer product when both vectors are sparse.
* @param v vector with which outer product should be computed
* @return the square matrix outer product between instance and v
* @throws IllegalArgumentException if v is not the same size as {@code this}
*/
public FieldMatrix outerProduct(SparseFieldVector v)
throws IllegalArgumentException {
checkVectorDimensions(v.getDimension());
SparseFieldMatrix res = new SparseFieldMatrix(field, virtualSize, virtualSize);
OpenIntToFieldHashMap.Iterator iter = entries.iterator();
while (iter.hasNext()) {
iter.advance();
OpenIntToFieldHashMap.Iterator iter2 = v.entries.iterator();
while (iter2.hasNext()) {
iter2.advance();
res.setEntry(iter.key(), iter2.key(), iter.value().multiply(iter2.value()));
}
}
return res;
}
/** {@inheritDoc} */
public FieldMatrix outerProduct(T[] v) throws IllegalArgumentException {
checkVectorDimensions(v.length);
FieldMatrix res = new SparseFieldMatrix(field, virtualSize, virtualSize);
OpenIntToFieldHashMap.Iterator iter = entries.iterator();
while (iter.hasNext()) {
iter.advance();
int row = iter.key();
FieldElementvalue = iter.value();
for (int col = 0; col < virtualSize; col++) {
res.setEntry(row, col, value.multiply(v[col]));
}
}
return res;
}
/** {@inheritDoc} */
public FieldMatrix outerProduct(FieldVector v)
throws IllegalArgumentException {
if(v instanceof SparseFieldVector)
return outerProduct((SparseFieldVector)v);
else
return outerProduct(v.toArray());
}
/** {@inheritDoc} */
public FieldVector projection(FieldVector v)
throws IllegalArgumentException {
checkVectorDimensions(v.getDimension());
return v.mapMultiply(dotProduct(v).divide(v.dotProduct(v)));
}
/** {@inheritDoc} */
public FieldVector projection(T[] v) throws IllegalArgumentException {
checkVectorDimensions(v.length);
return projection(new SparseFieldVector(field,v));
}
/** {@inheritDoc} */
public void set(T value) {
for (int i = 0; i < virtualSize; i++) {
setEntry(i, value);
}
}
/** {@inheritDoc} */
public void setEntry(int index, T value) throws MatrixIndexException {
checkIndex(index);
entries.put(index, value);
}
/** {@inheritDoc} */
public void setSubVector(int index, FieldVector v)
throws MatrixIndexException {
checkIndex(index);
checkIndex(index + v.getDimension() - 1);
setSubVector(index, v.getData());
}
/** {@inheritDoc} */
public void setSubVector(int index, T[] v) throws MatrixIndexException {
checkIndex(index);
checkIndex(index + v.length - 1);
for (int i = 0; i < v.length; i++) {
setEntry(i + index, v[i]);
}
}
/**
* Optimized method to subtract SparseRealVectors.
* @param v The vector to subtract from this
* @return The difference of this and v
* @throws IllegalArgumentException If the dimensions don't match
*/
public SparseFieldVector subtract(SparseFieldVector v) throws IllegalArgumentException{
checkVectorDimensions(v.getDimension());
SparseFieldVector res = (SparseFieldVector)copy();
OpenIntToFieldHashMap.Iterator iter = v.getEntries().iterator();
while (iter.hasNext()) {
iter.advance();
int key = iter.key();
if (entries.containsKey(key)) {
res.setEntry(key, entries.get(key).subtract(iter.value()));
} else {
res.setEntry(key, field.getZero().subtract(iter.value()));
}
}
return res;
}
/** {@inheritDoc} */
public FieldVector subtract(FieldVector v)
throws IllegalArgumentException {
if(v instanceof SparseFieldVector)
return subtract((SparseFieldVector)v);
else
return subtract(v.toArray());
}
/** {@inheritDoc} */
public FieldVector subtract(T[] v) throws IllegalArgumentException {
checkVectorDimensions(v.length);
SparseFieldVector res = new SparseFieldVector(this);
for (int i = 0; i < v.length; i++) {
if (entries.containsKey(i)) {
res.setEntry(i, entries.get(i).subtract(v[i]));
} else {
res.setEntry(i, field.getZero().subtract(v[i]));
}
}
return res;
}
/** {@inheritDoc} */
public T[] toArray() {
return getData();
}
/**
* Check if an index is valid.
*
* @param index
* index to check
* @exception MatrixIndexException
* if index is not valid
*/
private void checkIndex(final int index) throws MatrixIndexException {
if (index < 0 || index >= getDimension()) {
throw new MatrixIndexException(
"index {0} out of allowed range [{1}, {2}]",
index, 0, getDimension() - 1);
}
}
/**
* Check if instance dimension is equal to some expected value.
*
* @param n
* expected dimension.
* @exception IllegalArgumentException
* if the dimension is inconsistent with vector size
*/
protected void checkVectorDimensions(int n) throws IllegalArgumentException {
if (getDimension() != n) {
throw MathRuntimeException.createIllegalArgumentException(
"vector length mismatch: got {0} but expected {1}",
getDimension(), n);
}
}
/** {@inheritDoc} */
public FieldVector add(FieldVector v) throws IllegalArgumentException {
if (v instanceof SparseFieldVector) {
return add((SparseFieldVector)v);
} else {
return add(v.toArray());
}
}
/** Build an array of elements.
* @param length size of the array to build
* @return a new array
*/
@SuppressWarnings("unchecked")
private T[] buildArray(final int length) {
return (T[]) Array.newInstance(field.getZero().getClass(), length);
}
/** {@inheritDoc} */
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((field == null) ? 0 : field.hashCode());
result = prime * result + virtualSize;
OpenIntToFieldHashMap.Iterator iter = entries.iterator();
while (iter.hasNext()) {
iter.advance();
int temp = iter.value().hashCode();
result = prime * result + temp;
}
return result;
}
/** {@inheritDoc} */
@SuppressWarnings("unchecked")
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (!(obj instanceof SparseFieldVector)) {
return false;
}
SparseFieldVector other = (SparseFieldVector) obj;
if (field == null) {
if (other.field != null) {
return false;
}
} else if (!field.equals(other.field)) {
return false;
}
if (virtualSize != other.virtualSize) {
return false;
}
OpenIntToFieldHashMap.Iterator iter = entries.iterator();
while (iter.hasNext()) {
iter.advance();
T test = other.getEntry(iter.key());
if (!test.equals(iter.value())) {
return false;
}
}
iter = other.getEntries().iterator();
while (iter.hasNext()) {
iter.advance();
T test = iter.value();
if (!test.equals(getEntry(iter.key()))) {
return false;
}
}
return true;
}
}
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