/*
* 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.util.Arrays;
import java.util.Iterator;
import org.apache.commons.math.analysis.UnivariateRealFunction;
import org.apache.commons.math.exception.NullArgumentException;
import org.apache.commons.math.exception.DimensionMismatchException;
import org.apache.commons.math.exception.NumberIsTooLargeException;
import org.apache.commons.math.exception.MathArithmeticException;
import org.apache.commons.math.exception.util.LocalizedFormats;
import org.apache.commons.math.util.MathUtils;
import org.apache.commons.math.util.FastMath;
/**
* This class implements the {@link RealVector} interface with a double array.
* @version $Id: ArrayRealVector.java 1131229 2011-06-03 20:49:25Z luc $
* @since 2.0
*/
public class ArrayRealVector extends AbstractRealVector implements Serializable {
/** Serializable version identifier. */
private static final long serialVersionUID = -1097961340710804027L;
/** Default format. */
private static final RealVectorFormat DEFAULT_FORMAT = RealVectorFormat.getInstance();
/** Entries of the vector. */
protected double data[];
/**
* Build a 0-length vector.
* Zero-length vectors may be used to initialized construction of vectors
* by data gathering. We start with zero-length and use either the {@link
* #ArrayRealVector(ArrayRealVector, ArrayRealVector)} constructor
* or one of the {@code append} method ({@link #append(double)}, {@link
* #append(double[])}, {@link #append(ArrayRealVector)}) to gather data
* into this vector.
*/
public ArrayRealVector() {
data = new double[0];
}
/**
* Construct a vector of zeroes.
*
* @param size Size of the vector.
*/
public ArrayRealVector(int size) {
data = new double[size];
}
/**
* Construct a vector with preset values.
*
* @param size Size of the vector
* @param preset All entries will be set with this value.
*/
public ArrayRealVector(int size, double preset) {
data = new double[size];
Arrays.fill(data, preset);
}
/**
* Construct a vector from an array, copying the input array.
*
* @param d Array.
* @throws NullArgumentException if {@code d} is {@code null}.
*/
public ArrayRealVector(double[] d) {
data = d.clone();
}
/**
* Create a new ArrayRealVector using the input array as the underlying
* data array.
* If an array is built specially in order to be embedded in a
* ArrayRealVector and not used directly, the {@code copyArray} may be
* set to {@code false}. This will prevent the copying and improve
* performance as no new array will be built and no data will be copied.
*
* @param d Data for the new vector.
* @param copyArray if {@code true}, the input array will be copied,
* otherwise it will be referenced.
* @throws NullArgumentException if {@code d} is {@code null}.
* @see #ArrayRealVector(double[])
*/
public ArrayRealVector(double[] d, boolean copyArray) {
if (d == null) {
throw new NullArgumentException();
}
data = copyArray ? d.clone() : d;
}
/**
* Construct a vector from part of a array.
*
* @param d Array.
* @param pos Position of first entry.
* @param size Number of entries to copy.
* @throws NullArgumentException if {@code d} is {@code null}.
* @throws NumberIsTooLargeException if the size of {@code d} is less
* than {@code pos + size}.
*/
public ArrayRealVector(double[] d, int pos, int size) {
if (d == null) {
throw new NullArgumentException();
}
if (d.length < pos + size) {
throw new NumberIsTooLargeException(pos + size, d.length, true);
}
data = new double[size];
System.arraycopy(d, pos, data, 0, size);
}
/**
* Construct a vector from an array.
* @param d array of Doubles.
*/
public ArrayRealVector(Double[] d) {
data = new double[d.length];
for (int i = 0; i < d.length; i++) {
data[i] = d[i].doubleValue();
}
}
/**
* Construct a vector from part of an array.
*
* @param d Array.
* @param pos Position of first entry.
* @param size Number of entries to copy.
* @throws NullArgumentException if {@code d} is {@code null}.
* @throws NumberIsTooLargeException if the size of {@code d} is less
* than {@code pos + size}.
*/
public ArrayRealVector(Double[] d, int pos, int size) {
if (d == null) {
throw new NullArgumentException();
}
if (d.length < pos + size) {
throw new NumberIsTooLargeException(pos + size, d.length, true);
}
data = new double[size];
for (int i = pos; i < pos + size; i++) {
data[i - pos] = d[i].doubleValue();
}
}
/**
* Construct a vector from another vector, using a deep copy.
*
* @param v vector to copy.
* @throws NullArgumentException if {@code v} is {@code null}.
*/
public ArrayRealVector(RealVector v) {
if (v == null) {
throw new NullArgumentException();
}
data = new double[v.getDimension()];
for (int i = 0; i < data.length; ++i) {
data[i] = v.getEntry(i);
}
}
/**
* Construct a vector from another vector, using a deep copy.
*
* @param v Vector to copy.
* @throws NullArgumentException if {@code v} is {@code null}.
*/
public ArrayRealVector(ArrayRealVector v) {
this(v, true);
}
/**
* Construct a vector from another vector.
*
* @param v Vector to copy.
* @param deep If {@code true} perform a deep copy, otherwise perform a
* shallow copy.
*/
public ArrayRealVector(ArrayRealVector v, boolean deep) {
data = deep ? v.data.clone() : v.data;
}
/**
* Construct a vector by appending one vector to another vector.
* @param v1 First vector (will be put in front of the new vector).
* @param v2 Second vector (will be put at back of the new vector).
*/
public ArrayRealVector(ArrayRealVector v1, ArrayRealVector v2) {
data = new double[v1.data.length + v2.data.length];
System.arraycopy(v1.data, 0, data, 0, v1.data.length);
System.arraycopy(v2.data, 0, data, v1.data.length, v2.data.length);
}
/**
* Construct a vector by appending one vector to another vector.
* @param v1 First vector (will be put in front of the new vector).
* @param v2 Second vector (will be put at back of the new vector).
*/
public ArrayRealVector(ArrayRealVector v1, RealVector v2) {
final int l1 = v1.data.length;
final int l2 = v2.getDimension();
data = new double[l1 + l2];
System.arraycopy(v1.data, 0, data, 0, l1);
for (int i = 0; i < l2; ++i) {
data[l1 + i] = v2.getEntry(i);
}
}
/**
* Construct a vector by appending one vector to another vector.
* @param v1 First vector (will be put in front of the new vector).
* @param v2 Second vector (will be put at back of the new vector).
*/
public ArrayRealVector(RealVector v1, ArrayRealVector v2) {
final int l1 = v1.getDimension();
final int l2 = v2.data.length;
data = new double[l1 + l2];
for (int i = 0; i < l1; ++i) {
data[i] = v1.getEntry(i);
}
System.arraycopy(v2.data, 0, data, l1, l2);
}
/**
* Construct a vector by appending one vector to another vector.
* @param v1 First vector (will be put in front of the new vector).
* @param v2 Second vector (will be put at back of the new vector).
*/
public ArrayRealVector(ArrayRealVector v1, double[] v2) {
final int l1 = v1.getDimension();
final int l2 = v2.length;
data = new double[l1 + l2];
System.arraycopy(v1.data, 0, data, 0, l1);
System.arraycopy(v2, 0, data, l1, l2);
}
/**
* Construct a vector by appending one vector to another vector.
* @param v1 First vector (will be put in front of the new vector).
* @param v2 Second vector (will be put at back of the new vector).
*/
public ArrayRealVector(double[] v1, ArrayRealVector v2) {
final int l1 = v1.length;
final int l2 = v2.getDimension();
data = new double[l1 + l2];
System.arraycopy(v1, 0, data, 0, l1);
System.arraycopy(v2.data, 0, data, l1, l2);
}
/**
* Construct a vector by appending one vector to another vector.
* @param v1 first vector (will be put in front of the new vector)
* @param v2 second vector (will be put at back of the new vector)
*/
public ArrayRealVector(double[] v1, double[] v2) {
final int l1 = v1.length;
final int l2 = v2.length;
data = new double[l1 + l2];
System.arraycopy(v1, 0, data, 0, l1);
System.arraycopy(v2, 0, data, l1, l2);
}
/** {@inheritDoc} */
@Override
public ArrayRealVector copy() {
return new ArrayRealVector(this, true);
}
/** {@inheritDoc} */
@Override
public RealVector add(RealVector v) {
if (v instanceof ArrayRealVector) {
return add((ArrayRealVector) v);
} else {
checkVectorDimensions(v);
double[] out = data.clone();
Iterator<Entry> it = v.sparseIterator();
Entry e;
while (it.hasNext() && (e = it.next()) != null) {
out[e.getIndex()] += e.getValue();
}
return new ArrayRealVector(out, false);
}
}
/** {@inheritDoc} */
@Override
public RealVector add(double[] v) {
checkVectorDimensions(v.length);
double[] out = data.clone();
for (int i = 0; i < data.length; i++) {
out[i] += v[i];
}
return new ArrayRealVector(out, false);
}
/**
* Add {@code v} to this vector.
*
* @param v Vector to be added
* @return {@code this} + v.
* @throws DimensionMismatchException if {@code v} is not the same
* size as this vector.
*/
public ArrayRealVector add(ArrayRealVector v) {
return (ArrayRealVector) add(v.data);
}
/** {@inheritDoc} */
@Override
public RealVector subtract(RealVector v) {
if (v instanceof ArrayRealVector) {
return subtract((ArrayRealVector) v);
} else {
checkVectorDimensions(v);
double[] out = data.clone();
Iterator<Entry> it = v.sparseIterator();
Entry e;
while(it.hasNext() && (e = it.next()) != null) {
out[e.getIndex()] -= e.getValue();
}
return new ArrayRealVector(out, false);
}
}
/** {@inheritDoc} */
@Override
public RealVector subtract(double[] v) {
checkVectorDimensions(v.length);
double[] out = data.clone();
for (int i = 0; i < data.length; i++) {
out[i] -= v[i];
}
return new ArrayRealVector(out, false);
}
/**
* Subtract {@code v} from this vector.
*
* @param v Vector to be subtracted.
* @return {@code this} - v.
* @throws DimensionMismatchException if {@code v} is not the
* same size as this vector.
*/
public ArrayRealVector subtract(ArrayRealVector v) {
return (ArrayRealVector) subtract(v.data);
}
/** {@inheritDoc} */
@Override
public ArrayRealVector map(UnivariateRealFunction function) {
return copy().mapToSelf(function);
}
/** {@inheritDoc} */
@Override
public ArrayRealVector mapToSelf(UnivariateRealFunction function) {
for (int i = 0; i < data.length; i++) {
data[i] = function.value(data[i]);
}
return this;
}
/** {@inheritDoc} */
@Override
public RealVector mapAddToSelf(double d) {
for (int i = 0; i < data.length; i++) {
data[i] = data[i] + d;
}
return this;
}
/** {@inheritDoc} */
@Override
public RealVector mapSubtractToSelf(double d) {
for (int i = 0; i < data.length; i++) {
data[i] = data[i] - d;
}
return this;
}
/** {@inheritDoc} */
@Override
public RealVector mapMultiplyToSelf(double d) {
for (int i = 0; i < data.length; i++) {
data[i] = data[i] * d;
}
return this;
}
/** {@inheritDoc} */
@Override
public RealVector mapDivideToSelf(double d) {
for (int i = 0; i < data.length; i++) {
data[i] = data[i] / d;
}
return this;
}
/** {@inheritDoc} */
public RealVector ebeMultiply(RealVector v) {
if (v instanceof ArrayRealVector) {
return ebeMultiply((ArrayRealVector) v);
} else {
checkVectorDimensions(v);
double[] out = data.clone();
for (int i = 0; i < data.length; i++) {
out[i] *= v.getEntry(i);
}
return new ArrayRealVector(out, false);
}
}
/** {@inheritDoc} */
@Override
public RealVector ebeMultiply(double[] v) {
checkVectorDimensions(v.length);
double[] out = data.clone();
for (int i = 0; i < data.length; i++) {
out[i] *= v[i];
}
return new ArrayRealVector(out, false);
}
/**
* Element-by-element multiplication.
* @param v Vector by which instance elements must be multiplied.
* @return a Vector containing {@code this[i] * v[i]} for all {@code i}.
* @exception DimensionMismatchException if {@code v} is not the same
* size as this vector.
*/
public ArrayRealVector ebeMultiply(ArrayRealVector v) {
return (ArrayRealVector) ebeMultiply(v.data);
}
/** {@inheritDoc} */
public RealVector ebeDivide(RealVector v) {
if (v instanceof ArrayRealVector) {
return ebeDivide((ArrayRealVector) v);
} else {
checkVectorDimensions(v);
double[] out = data.clone();
for (int i = 0; i < data.length; i++) {
out[i] /= v.getEntry(i);
}
return new ArrayRealVector(out, false);
}
}
/** {@inheritDoc} */
@Override
public RealVector ebeDivide(double[] v) {
checkVectorDimensions(v.length);
double[] out = data.clone();
for (int i = 0; i < data.length; i++) {
out[i] /= v[i];
}
return new ArrayRealVector(out, false);
}
/**
* Element-by-element division.
*
* @param v Vector by which instance elements must be divided.
* @return a vector containing {@code this[i] / v[i]} for all {@code i}.
* @exception DimensionMismatchException if {@code v} is not the same
* size as this vector.
*/
public ArrayRealVector ebeDivide(ArrayRealVector v) {
return (ArrayRealVector) ebeDivide(v.data);
}
/** {@inheritDoc} */
@Override
public double[] getData() {
return data.clone();
}
/**
* Get a reference to the underlying data array.
* This method does not make a fresh copy of the underlying data.
*
* @return the array of entries.
*/
public double[] getDataRef() {
return data;
}
/** {@inheritDoc} */
@Override
public double dotProduct(RealVector v) {
if (v instanceof ArrayRealVector) {
return dotProduct((ArrayRealVector) v);
} else {
checkVectorDimensions(v);
double dot = 0;
Iterator<Entry> it = v.sparseIterator();
Entry e;
while(it.hasNext() && (e = it.next()) != null) {
dot += data[e.getIndex()] * e.getValue();
}
return dot;
}
}
/** {@inheritDoc} */
@Override
public double dotProduct(double[] v) {
checkVectorDimensions(v.length);
double dot = 0;
for (int i = 0; i < data.length; i++) {
dot += data[i] * v[i];
}
return dot;
}
/**
* Compute the dot product.
*
* @param v Vector with which dot product should be computed
* @return the scalar dot product between instance and {@code v}.
* @throws DimensionMismatchException if {@code v} is not the same
* size as this vector.
*/
public double dotProduct(ArrayRealVector v) {
return dotProduct(v.data);
}
/** {@inheritDoc} */
@Override
public double getNorm() {
double sum = 0;
for (double a : data) {
sum += a * a;
}
return FastMath.sqrt(sum);
}
/** {@inheritDoc} */
@Override
public double getL1Norm() {
double sum = 0;
for (double a : data) {
sum += FastMath.abs(a);
}
return sum;
}
/** {@inheritDoc} */
@Override
public double getLInfNorm() {
double max = 0;
for (double a : data) {
max = FastMath.max(max, FastMath.abs(a));
}
return max;
}
/** {@inheritDoc} */
@Override
public double getDistance(RealVector v) {
if (v instanceof ArrayRealVector) {
return getDistance((ArrayRealVector) v);
} else {
checkVectorDimensions(v);
double sum = 0;
for (int i = 0; i < data.length; ++i) {
final double delta = data[i] - v.getEntry(i);
sum += delta * delta;
}
return FastMath.sqrt(sum);
}
}
/** {@inheritDoc} */
@Override
public double getDistance(double[] v) {
checkVectorDimensions(v.length);
double sum = 0;
for (int i = 0; i < data.length; ++i) {
final double delta = data[i] - v[i];
sum += delta * delta;
}
return FastMath.sqrt(sum);
}
/**
* Distance between two vectors.
* This method computes the distance consistent with the
* L<sub>2</sub> norm, i.e. the square root of the sum of
* elements differences, or euclidian distance.
*
* @param v Vector to which distance is requested.
* @return the distance between two vectors.
* @throws DimensionMismatchException if {@code v} is not the same size as
* this vector.
* @see #getDistance(RealVector)
* @see #getL1Distance(ArrayRealVector)
* @see #getLInfDistance(ArrayRealVector)
* @see #getNorm()
*/
public double getDistance(ArrayRealVector v) {
return getDistance(v.data);
}
/** {@inheritDoc} */
@Override
public double getL1Distance(RealVector v) {
if (v instanceof ArrayRealVector) {
return getL1Distance((ArrayRealVector) v);
} else {
checkVectorDimensions(v);
double sum = 0;
for (int i = 0; i < data.length; ++i) {
final double delta = data[i] - v.getEntry(i);
sum += FastMath.abs(delta);
}
return sum;
}
}
/** {@inheritDoc} */
@Override
public double getL1Distance(double[] v) {
checkVectorDimensions(v.length);
double sum = 0;
for (int i = 0; i < data.length; ++i) {
final double delta = data[i] - v[i];
sum += FastMath.abs(delta);
}
return sum;
}
/**
* Distance between two vectors.
* This method computes the distance consistent with
* L<sub>1</sub> norm, i.e. the sum of the absolute values of
* elements differences.
*
* @param v Vector to which distance is requested.
* @return the distance between two vectors.
* @throws DimensionMismatchException if {@code v} is not the same size
* as this vector.
* @see #getDistance(RealVector)
* @see #getL1Distance(ArrayRealVector)
* @see #getLInfDistance(ArrayRealVector)
* @see #getNorm()
*/
public double getL1Distance(ArrayRealVector v) {
return getL1Distance(v.data);
}
/** {@inheritDoc} */
@Override
public double getLInfDistance(RealVector v) {
if (v instanceof ArrayRealVector) {
return getLInfDistance((ArrayRealVector) v);
} else {
checkVectorDimensions(v);
double max = 0;
for (int i = 0; i < data.length; ++i) {
final double delta = data[i] - v.getEntry(i);
max = FastMath.max(max, FastMath.abs(delta));
}
return max;
}
}
/** {@inheritDoc} */
@Override
public double getLInfDistance(double[] v) {
checkVectorDimensions(v.length);
double max = 0;
for (int i = 0; i < data.length; ++i) {
final double delta = data[i] - v[i];
max = FastMath.max(max, FastMath.abs(delta));
}
return max;
}
/**
* Distance between two vectors.
* This method computes the distance consistent with
* L<sub>∞</sub> norm, i.e. the max of the absolute values of
* elements differences.
*
* @param v Vector to which distance is requested.
* @return the distance between two vectors.
* @exception IllegalArgumentException if {@code v} is not the same size as this
* @see #getDistance(RealVector)
* @see #getL1Distance(ArrayRealVector)
* @see #getLInfDistance(ArrayRealVector)
* @see #getNorm()
*/
public double getLInfDistance(ArrayRealVector v) {
return getLInfDistance(v.data);
}
/** {@inheritDoc} */
@Override
public RealVector unitVector() {
final double norm = getNorm();
if (norm == 0) {
throw new MathArithmeticException(LocalizedFormats.ZERO_NORM);
}
return mapDivide(norm);
}
/** {@inheritDoc} */
@Override
public void unitize() {
final double norm = getNorm();
if (norm == 0) {
throw new MathArithmeticException(LocalizedFormats.ZERO_NORM);
}
mapDivideToSelf(norm);
}
/** {@inheritDoc} */
public RealVector projection(RealVector v) {
return v.mapMultiply(dotProduct(v) / v.dotProduct(v));
}
/** {@inheritDoc} */
@Override
public RealVector projection(double[] v) {
return projection(new ArrayRealVector(v, false));
}
/**
* Find the orthogonal projection of this vector onto another vector.
*
* @param v Vector onto which instance must be projected.
* @return Projection of this instance onto {@code v}.
* @throws DimensionMismatchException if {@code v} is not the same size as
* this vector.
*/
public ArrayRealVector projection(ArrayRealVector v) {
return (ArrayRealVector) v.mapMultiply(dotProduct(v) / v.dotProduct(v));
}
/** {@inheritDoc} */
@Override
public RealMatrix outerProduct(RealVector v) {
if (v instanceof ArrayRealVector) {
return outerProduct((ArrayRealVector) v);
} else {
final int m = data.length;
final int n = v.getDimension();
final RealMatrix out = MatrixUtils.createRealMatrix(m, n);
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
out.setEntry(i, j, data[i] * v.getEntry(j));
}
}
return out;
}
}
/**
* Compute the outer product.
* @param v Vector with which outer product should be computed.
* @return the square matrix outer product between this instance and {@code v}.
* @throws DimensionMismatchException if {@code v} is not the same
* size as this vector.
*/
public RealMatrix outerProduct(ArrayRealVector v) {
return outerProduct(v.data);
}
/** {@inheritDoc} */
@Override
public RealMatrix outerProduct(double[] v) {
final int m = data.length;
final int n = v.length;
final RealMatrix out = MatrixUtils.createRealMatrix(m, n);
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
out.setEntry(i, j, data[i] * v[j]);
}
}
return out;
}
/** {@inheritDoc} */
public double getEntry(int index) {
return data[index];
}
/** {@inheritDoc} */
public int getDimension() {
return data.length;
}
/** {@inheritDoc} */
public RealVector append(RealVector v) {
try {
return new ArrayRealVector(this, (ArrayRealVector) v);
} catch (ClassCastException cce) {
return new ArrayRealVector(this, v);
}
}
/**
* Construct a vector by appending a vector to this vector.
*
* @param v Vector to append to this one.
* @return a new vector.
*/
public ArrayRealVector append(ArrayRealVector v) {
return new ArrayRealVector(this, v);
}
/** {@inheritDoc} */
public RealVector append(double in) {
final double[] out = new double[data.length + 1];
System.arraycopy(data, 0, out, 0, data.length);
out[data.length] = in;
return new ArrayRealVector(out, false);
}
/** {@inheritDoc} */
public RealVector append(double[] in) {
return new ArrayRealVector(this, in);
}
/** {@inheritDoc} */
public RealVector getSubVector(int index, int n) {
ArrayRealVector out = new ArrayRealVector(n);
try {
System.arraycopy(data, index, out.data, 0, n);
} catch (IndexOutOfBoundsException e) {
checkIndex(index);
checkIndex(index + n - 1);
}
return out;
}
/** {@inheritDoc} */
public void setEntry(int index, double value) {
try {
data[index] = value;
} catch (IndexOutOfBoundsException e) {
checkIndex(index);
}
}
/** {@inheritDoc} */
@Override
public void setSubVector(int index, RealVector v) {
try {
try {
set(index, (ArrayRealVector) v);
} catch (ClassCastException cce) {
for (int i = index; i < index + v.getDimension(); ++i) {
data[i] = v.getEntry(i - index);
}
}
} catch (IndexOutOfBoundsException e) {
checkIndex(index);
checkIndex(index + v.getDimension() - 1);
}
}
/** {@inheritDoc} */
@Override
public void setSubVector(int index, double[] v) {
try {
System.arraycopy(v, 0, data, index, v.length);
} catch (IndexOutOfBoundsException e) {
checkIndex(index);
checkIndex(index + v.length - 1);
}
}
/**
* Set a set of consecutive elements.
*
* @param index Index of first element to be set.
* @param v Vector containing the values to set.
* @throws org.apache.commons.math.exception.OutOfRangeException
* if the index is inconsistent with the vector size.
*/
public void set(int index, ArrayRealVector v) {
setSubVector(index, v.data);
}
/** {@inheritDoc} */
@Override
public void set(double value) {
Arrays.fill(data, value);
}
/** {@inheritDoc} */
@Override
public double[] toArray(){
return data.clone();
}
/** {@inheritDoc} */
@Override
public String toString(){
return DEFAULT_FORMAT.format(this);
}
/**
* Check if instance and specified vectors have the same dimension.
*
* @param v Vector to compare instance with.
* @throws DimensionMismatchException if the vectors do not
* have the same dimension.
*/
@Override
protected void checkVectorDimensions(RealVector v) {
checkVectorDimensions(v.getDimension());
}
/**
* Check if instance dimension is equal to some expected value.
*
* @param n Expected dimension.
* @throws DimensionMismatchException if the dimension is
* inconsistent with vector size.
*/
@Override
protected void checkVectorDimensions(int n) {
if (data.length != n) {
throw new DimensionMismatchException(data.length, n);
}
}
/**
* Check if any coordinate of this vector is {@code NaN}.
*
* @return {@code true} if any coordinate of this vector is {@code NaN},
* {@code false} otherwise.
*/
public boolean isNaN() {
for (double v : data) {
if (Double.isNaN(v)) {
return true;
}
}
return false;
}
/**
* Check whether any coordinate of this vector is infinite and none
* are {@code NaN}.
*
* @return {@code true} if any coordinate of this vector is infinite and
* none are {@code NaN}, {@code false} otherwise.
*/
public boolean isInfinite() {
if (isNaN()) {
return false;
}
for (double v : data) {
if (Double.isInfinite(v)) {
return true;
}
}
return false;
}
/**
* Test for the equality of two real vectors.
* If all coordinates of two real vectors are exactly the same, and none are
* {@code NaN}, the two real vectors are considered to be equal.
* {@code NaN} coordinates are considered to affect globally the vector
* and be equals to each other - i.e, if either (or all) coordinates of the
* real vector are equal to {@code NaN}, the real vector is equal to
* a vector with all {@code NaN} coordinates.
*
* @param other Object to test for equality.
* @return {@code true} if two vector objects are equal, {@code false} if
* {@code other} is null, not an instance of {@code RealVector}, or
* not equal to this {@code RealVector} instance.
*/
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (other == null || !(other instanceof RealVector)) {
return false;
}
RealVector rhs = (RealVector) other;
if (data.length != rhs.getDimension()) {
return false;
}
if (rhs.isNaN()) {
return this.isNaN();
}
for (int i = 0; i < data.length; ++i) {
if (data[i] != rhs.getEntry(i)) {
return false;
}
}
return true;
}
/**
* Get a hashCode for the real vector.
* All {@code NaN} values have the same hash code.
*
* @return a hash code.
*/
@Override
public int hashCode() {
if (isNaN()) {
return 9;
}
return MathUtils.hash(data);
}
}