/*
* $RCSfile: Vector.java,v $
* $Revision: 1.2 $
* $Date: 2007/06/30 17:30:33 $
* $Author: wojna $
*
* Copyright (C) 2002 - 2007 Logic Group, Institute of Mathematics, Warsaw University
*
* This file is part of Rseslib.
*
* Rseslib is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* Rseslib is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package rseslib.structure.vector;
import java.io.Serializable;
/**
* Vector from a multidimensional real value space
* with variety of vector operations.
*
* @author Rafal Falkowski, Lukasz Ligowski, Arkadiusz Wojna
*/
public class Vector implements Comparable, Serializable
{
/** Serialization version. */
private static final long serialVersionUID = 1L;
/** Vector coordinates. */
double[] m_arrCoordinates;
/**
* Constructor sets initial values of coordinates to 0.
*
* @param dim Vector dimension.
*/
public Vector(int dim)
{
m_arrCoordinates = new double[dim];
}
/**
* Constructs a vector identical with a given template.
*
* @param template Original template.
*/
public Vector(Vector template)
{
m_arrCoordinates = new double[template.dimension()];
for (int coord = 0; coord < m_arrCoordinates.length; coord++)
m_arrCoordinates[coord] = template.get(coord);
}
/**
* Returns vector dimension.
*
* @return Vector dimension.
*/
public int dimension()
{
return m_arrCoordinates.length;
}
/**
* Sets the value of an indicated coordinate.
*
* @param coord Coordinate index.
* @param value New coordinate value.
*/
public void set(int coord, double value)
{
m_arrCoordinates[coord] = value;
}
/**
* Sets the vector values identically as in a given template.
*
* @param template Original template.
*/
public void set(Vector template)
{
for (int coord = 0; coord < m_arrCoordinates.length; coord++)
m_arrCoordinates[coord] = template.get(coord);
}
/**
* Increments an indicated coordinate by 1.
*
* @param coord Coordinate index.
*/
public void increment(int coord)
{
m_arrCoordinates[coord] += 1;
}
/**
* Decrements an indicated coordinate by 1.
*
* @param coord Coordinate index.
*/
public void decrement(int coord)
{
m_arrCoordinates[coord] -= 1;
}
/**
* Gets the value of an indicated coordinate.
*
* @param coord Coordinate index.
* @return Coordinate value.
*/
public double get(int coord)
{
return m_arrCoordinates[coord];
}
/**
* Resets all coordinates to 0.
*/
public void reset()
{
for (int c = 0; c < m_arrCoordinates.length; c++) m_arrCoordinates[c] = 0;
}
/**
* Adds a given vector.
*
* @param vec Vector to be added.
*/
public void add(Vector vec)
{
for (int c = 0; c < m_arrCoordinates.length; c++) m_arrCoordinates[c] += vec.get(c);
}
/**
* Subtracts a given vector.
*
* @param vec Subtracted vector.
*/
public void subtract(Vector vec)
{
for (int c = 0; c < m_arrCoordinates.length; c++) m_arrCoordinates[c] -= vec.get(c);
}
/**
* Multiplies this vector.
*
* @param coeff Multiplication factor.
*/
public void multiply(double coeff)
{
for (int c = 0; c < m_arrCoordinates.length; c++) m_arrCoordinates[c] *= coeff;
}
/**
* Multiplies i`th coordinate.
*
* @param i Coordinate.
* @param multiplier Multiplier.
*/
public void multiply(int i,double multiplier)
{
m_arrCoordinates[i] *= multiplier;
}
/**
* Divides this vector.
*
* @param div Divisor.
*/
public void divide(double div)
{
for (int c = 0; c < m_arrCoordinates.length; c++) m_arrCoordinates[c] /= div;
}
/**
* Divides i`th coordinate.
*
* @param i Coordinate.
* @param div Divisor.
*/
public void divide(int i,double div)
{
m_arrCoordinates[i] /= div;
}
/**
* Returns the scalar product of this vector and the vector given as the parameter.
*
* @param vec Vector used to compute the product.
*
* @return Scalar product.
*/
public double scalarProduct(Vector vec)
{
double sum = 0;
for (int att = 0; att < m_arrCoordinates.length; att++)
sum += m_arrCoordinates[att]*vec.get(att);
return sum;
}
/**
* Deflates this vector by a given vector.
* it means that this method performs the projection of this
* vector onto the space orthogonal to a given vector.
*
* @param vec Vector used to deflate this vector.
*/
public void deflate(Vector vec)
{
// tzn: x = x - (vec^T * x) * w
double vecx = vec.scalarProduct(this);
for(int att = 0; att < m_arrCoordinates.length; att++)
set(att, get(att) - vecx*vec.get(att));
}
/**
* Returns the city-Manhattan norm of this vector.
*
* @return The city-Manhattan norm.
*/
public double cityNorm()
{
double sum = 0;
for (int c = 0; c < m_arrCoordinates.length; c++)
if (m_arrCoordinates[c] >= 0) sum += m_arrCoordinates[c];
else sum -= m_arrCoordinates[c];
return sum;
}
/**
* Normalises this vector to 1 according to city metric.
*/
public void normalizeWithCityNorm()
{
double norm = cityNorm();
for (int c = 0; c < m_arrCoordinates.length; c++) m_arrCoordinates[c] /= norm;
}
/**
* Returns the square Euclidean norm of this vector.
*
* @return The square Euclidean norm.
*/
public double squareEuclideanNorm()
{
double sum = 0;
for (int c = 0; c < m_arrCoordinates.length; c++)
sum += m_arrCoordinates[c]*m_arrCoordinates[c];
return sum;
}
/**
* Returns the Euclidean norm of this vector.
*
* @return The Euclidean norm.
*/
public double euclideanNorm()
{
return Math.sqrt(squareEuclideanNorm());
}
/**
* Normalises this vector to 1 according to the Euclidean metric.
*/
public void normalizeWithEuclideanNorm()
{
double norm = euclideanNorm();
for (int c = 0; c < m_arrCoordinates.length; c++) m_arrCoordinates[c] /= norm;
}
/**
* Compares this vector with the specified vector o according to the lexicographical order.
* Returns -1, 0, or 1 as this vector is less than, equal to, or greater than the specified object.
*
* @param o The vector to be compared.
* @return The value -1, 0, or 1 as this vector is less than, equal to, or greater than the specified object.
*/
public int compareTo(Object o)
{
for (int coord = 0; coord < m_arrCoordinates.length && coord < ((Vector)o).dimension(); coord++)
if (m_arrCoordinates[coord] < ((Vector)o).get(coord)) return -1;
else if (m_arrCoordinates[coord] > ((Vector)o).get(coord)) return 1;
if (m_arrCoordinates.length < ((Vector)o).dimension()) return -1;
else if (m_arrCoordinates.length > ((Vector)o).dimension()) return 1;
return 0;
}
/**
* Return true if this vector and the specified vector o are the same
* and false otherwise.
*
* @param obj The vector to be compared.
* @return True if this vector and the specified vector o are the same and false otherwise.
*/
public boolean equals(Object obj)
{
if (m_arrCoordinates.length!=((Vector)obj).dimension()) return false;
for (int coord = 0; coord < m_arrCoordinates.length; coord++)
if (m_arrCoordinates[coord]!=((Vector)obj).get(coord)) return false;
return true;
}
/**
* Returns string representing this vector.
*
* @return String representing this vector.
*/
public String toString()
{
StringBuffer sb = new StringBuffer();
sb.append("[");
for (int d = 0; d < m_arrCoordinates.length; d++)
{
sb.append(m_arrCoordinates[d]);
if (d < m_arrCoordinates.length-1) sb.append(", ");
}
sb.append("]");
return sb.toString();
}
/**
* Returns Manhattan city distance between two vectors.
*
* @param vect1 The first vector to be compared.
* @param vect2 The second vector to be compared.
* @return Manhattan city distance between two vectors.
*/
public static double cityDist(Vector vect1, Vector vect2)
{
double dist = 0;
if (vect1.dimension() != vect2.dimension()) throw new RuntimeException("Compared vectors have different dimension "+vect1.dimension()+" and "+vect2.dimension());
for (int coord = 0; coord < vect1.dimension(); coord++)
dist += Math.abs(vect1.get(coord)-vect2.get(coord));
return dist;
}
/**
* Returns rank of the vector.
* Rank is a number of non-zero (and non Not-a-Number) parameters.
* @return rank of the vector
*/
public int rank()
{
int rank=0;
for (double d : m_arrCoordinates)
if (d!=0&&!Double.isNaN(d)) rank++;
return rank;
}
}
