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With inspiration from other libraries
/*
* 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.math3.geometry.euclidean.oned;
import java.text.NumberFormat;
import org.apache.commons.math3.exception.MathArithmeticException;
import org.apache.commons.math3.exception.util.LocalizedFormats;
import org.apache.commons.math3.geometry.Point;
import org.apache.commons.math3.geometry.Space;
import org.apache.commons.math3.geometry.Vector;
import org.apache.commons.math3.util.FastMath;
import org.apache.commons.math3.util.MathUtils;
/** This class represents a 1D vector.
* Instances of this class are guaranteed to be immutable.
* @since 3.0
*/
public class Vector1D implements Vector {
/** Origin (coordinates: 0). */
public static final Vector1D ZERO = new Vector1D(0.0);
/** Unit (coordinates: 1). */
public static final Vector1D ONE = new Vector1D(1.0);
// CHECKSTYLE: stop ConstantName
/** A vector with all coordinates set to NaN. */
public static final Vector1D NaN = new Vector1D(Double.NaN);
// CHECKSTYLE: resume ConstantName
/** A vector with all coordinates set to positive infinity. */
public static final Vector1D POSITIVE_INFINITY =
new Vector1D(Double.POSITIVE_INFINITY);
/** A vector with all coordinates set to negative infinity. */
public static final Vector1D NEGATIVE_INFINITY =
new Vector1D(Double.NEGATIVE_INFINITY);
/** Serializable UID. */
private static final long serialVersionUID = 7556674948671647925L;
/** Abscissa. */
private final double x;
/** Simple constructor.
* Build a vector from its coordinates
* @param x abscissa
* @see #getX()
*/
public Vector1D(double x) {
this.x = x;
}
/** Multiplicative constructor
* Build a vector from another one and a scale factor.
* The vector built will be a * u
* @param a scale factor
* @param u base (unscaled) vector
*/
public Vector1D(double a, Vector1D u) {
this.x = a * u.x;
}
/** Linear constructor
* Build a vector from two other ones and corresponding scale factors.
* The vector built will be a1 * u1 + a2 * u2
* @param a1 first scale factor
* @param u1 first base (unscaled) vector
* @param a2 second scale factor
* @param u2 second base (unscaled) vector
*/
public Vector1D(double a1, Vector1D u1, double a2, Vector1D u2) {
this.x = a1 * u1.x + a2 * u2.x;
}
/** Linear constructor
* Build a vector from three other ones and corresponding scale factors.
* The vector built will be a1 * u1 + a2 * u2 + a3 * u3
* @param a1 first scale factor
* @param u1 first base (unscaled) vector
* @param a2 second scale factor
* @param u2 second base (unscaled) vector
* @param a3 third scale factor
* @param u3 third base (unscaled) vector
*/
public Vector1D(double a1, Vector1D u1, double a2, Vector1D u2,
double a3, Vector1D u3) {
this.x = a1 * u1.x + a2 * u2.x + a3 * u3.x;
}
/** Linear constructor
* Build a vector from four other ones and corresponding scale factors.
* The vector built will be a1 * u1 + a2 * u2 + a3 * u3 + a4 * u4
* @param a1 first scale factor
* @param u1 first base (unscaled) vector
* @param a2 second scale factor
* @param u2 second base (unscaled) vector
* @param a3 third scale factor
* @param u3 third base (unscaled) vector
* @param a4 fourth scale factor
* @param u4 fourth base (unscaled) vector
*/
public Vector1D(double a1, Vector1D u1, double a2, Vector1D u2,
double a3, Vector1D u3, double a4, Vector1D u4) {
this.x = a1 * u1.x + a2 * u2.x + a3 * u3.x + a4 * u4.x;
}
/** Get the abscissa of the vector.
* @return abscissa of the vector
* @see #Vector1D(double)
*/
public double getX() {
return x;
}
/** {@inheritDoc} */
public Space getSpace() {
return Euclidean1D.getInstance();
}
/** {@inheritDoc} */
public Vector1D getZero() {
return ZERO;
}
/** {@inheritDoc} */
public double getNorm1() {
return FastMath.abs(x);
}
/** {@inheritDoc} */
public double getNorm() {
return FastMath.abs(x);
}
/** {@inheritDoc} */
public double getNormSq() {
return x * x;
}
/** {@inheritDoc} */
public double getNormInf() {
return FastMath.abs(x);
}
/** {@inheritDoc} */
public Vector1D add(Vector v) {
Vector1D v1 = (Vector1D) v;
return new Vector1D(x + v1.getX());
}
/** {@inheritDoc} */
public Vector1D add(double factor, Vector v) {
Vector1D v1 = (Vector1D) v;
return new Vector1D(x + factor * v1.getX());
}
/** {@inheritDoc} */
public Vector1D subtract(Vector p) {
Vector1D p3 = (Vector1D) p;
return new Vector1D(x - p3.x);
}
/** {@inheritDoc} */
public Vector1D subtract(double factor, Vector v) {
Vector1D v1 = (Vector1D) v;
return new Vector1D(x - factor * v1.getX());
}
/** {@inheritDoc} */
public Vector1D normalize() throws MathArithmeticException {
double s = getNorm();
if (s == 0) {
throw new MathArithmeticException(LocalizedFormats.CANNOT_NORMALIZE_A_ZERO_NORM_VECTOR);
}
return scalarMultiply(1 / s);
}
/** {@inheritDoc} */
public Vector1D negate() {
return new Vector1D(-x);
}
/** {@inheritDoc} */
public Vector1D scalarMultiply(double a) {
return new Vector1D(a * x);
}
/** {@inheritDoc} */
public boolean isNaN() {
return Double.isNaN(x);
}
/** {@inheritDoc} */
public boolean isInfinite() {
return !isNaN() && Double.isInfinite(x);
}
/** {@inheritDoc} */
public double distance1(Vector p) {
Vector1D p3 = (Vector1D) p;
final double dx = FastMath.abs(p3.x - x);
return dx;
}
/** {@inheritDoc}
* @deprecated as of 3.3, replaced with {@link #distance(Point)}
*/
@Deprecated
public double distance(Vector p) {
return distance((Point) p);
}
/** {@inheritDoc} */
public double distance(Point p) {
Vector1D p3 = (Vector1D) p;
final double dx = p3.x - x;
return FastMath.abs(dx);
}
/** {@inheritDoc} */
public double distanceInf(Vector p) {
Vector1D p3 = (Vector1D) p;
final double dx = FastMath.abs(p3.x - x);
return dx;
}
/** {@inheritDoc} */
public double distanceSq(Vector p) {
Vector1D p3 = (Vector1D) p;
final double dx = p3.x - x;
return dx * dx;
}
/** {@inheritDoc} */
public double dotProduct(final Vector v) {
final Vector1D v1 = (Vector1D) v;
return x * v1.x;
}
/** Compute the distance between two vectors according to the L2 norm.
* Calling this method is equivalent to calling:
* p1.subtract(p2).getNorm() except that no intermediate
* vector is built
* @param p1 first vector
* @param p2 second vector
* @return the distance between p1 and p2 according to the L2 norm
*/
public static double distance(Vector1D p1, Vector1D p2) {
return p1.distance(p2);
}
/** Compute the distance between two vectors according to the L∞ norm.
* Calling this method is equivalent to calling:
* p1.subtract(p2).getNormInf() except that no intermediate
* vector is built
* @param p1 first vector
* @param p2 second vector
* @return the distance between p1 and p2 according to the L∞ norm
*/
public static double distanceInf(Vector1D p1, Vector1D p2) {
return p1.distanceInf(p2);
}
/** Compute the square of the distance between two vectors.
* Calling this method is equivalent to calling:
* p1.subtract(p2).getNormSq() except that no intermediate
* vector is built
* @param p1 first vector
* @param p2 second vector
* @return the square of the distance between p1 and p2
*/
public static double distanceSq(Vector1D p1, Vector1D p2) {
return p1.distanceSq(p2);
}
/**
* Test for the equality of two 1D vectors.
*
* If all coordinates of two 1D vectors are exactly the same, and none are
* Double.NaN, the two 1D vectors are considered to be equal.
*
*
* NaN coordinates are considered to affect globally the vector
* and be equals to each other - i.e, if either (or all) coordinates of the
* 1D vector are equal to Double.NaN, the 1D vector is equal to
* {@link #NaN}.
*
*
* @param other Object to test for equality to this
* @return true if two 1D vector objects are equal, false if
* object is null, not an instance of Vector1D, or
* not equal to this Vector1D instance
*
*/
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (other instanceof Vector1D) {
final Vector1D rhs = (Vector1D)other;
if (rhs.isNaN()) {
return this.isNaN();
}
return x == rhs.x;
}
return false;
}
/**
* Get a hashCode for the 1D vector.
*
* All NaN values have the same hash code.
*
* @return a hash code value for this object
*/
@Override
public int hashCode() {
if (isNaN()) {
return 7785;
}
return 997 * MathUtils.hash(x);
}
/** Get a string representation of this vector.
* @return a string representation of this vector
*/
@Override
public String toString() {
return Vector1DFormat.getInstance().format(this);
}
/** {@inheritDoc} */
public String toString(final NumberFormat format) {
return new Vector1DFormat(format).format(this);
}
}