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package it.unimi.di.law.vector;
/*
* Copyright (C) 2008-2013 Paolo Boldi, Massimo Santini and Sebastiano Vigna
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by the Free
* Software Foundation; either version 3 of the License, or (at your option)
* any later version.
*
* This library 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 Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, see index[ lastIdx ]. */
private int lastIndexValue;
/** The value of index[ lastIdx + 1 ] (or size if lastIdx == nonZero - 1. */
private int lastIndexNextValue;
// ALERT: document that index is supposed to be SORTED!
/** Build a vector of given size from an array of values.
*
* @param size the size.
* @param value the value.
* @param index the index.
* @param id the id of description of this vector.
*/
private ImmutableSparseVector (final int size, final double[] value, final int[] index, final int id) {
super (size, false, id);
this.value = value;
this.index = index;
this.nonZero = index.length;
// reset last index
lastIndex = lastIndexValue = lastIndexNextValue = -1;
}
/** Returns an instance of given size from an array of values.
*
* @param size the size.
* @param value the value.
* @param index the index.
* @param id the id of description of this vector.
* @return an immutable vector.
*/
public static ImmutableSparseVector getInstance (final int size, final double[] value, final int[] index, final int id) {
// check for different length
if (value.length != index.length)
throw new IllegalArgumentException ("array with different size");
// check for negative value in index
for( int i = index.length; i-- != 0; )
if (index[i] < 0)
throw new IllegalArgumentException ("index with negative value");
return new ImmutableSparseVector (size, value, index, id);
}
/** Returns an instance containing all the values of a given vector larger or smaller of a given threshold.
* The vector will have size equal to the vector length.
*
* @param v the vector.
* @param threshold the threshold.
* @param id the id of description of this vector.
* @return an immutable vector
*/
public static ImmutableSparseVector getInstance (final Vector v, final double threshold, final int id) {
final IntArrayList indexList = new IntArrayList();
final DoubleArrayList valueList = new DoubleArrayList();
final int size = v.size;
// add value grater than threshold
for( int i = size; i-- != 0; ) {
final double d = v.get(i);
if ( d < -threshold || d > threshold ) {
indexList.add (i);
valueList.add (d);
}
}
return new ImmutableSparseVector (size, valueList.toDoubleArray(), indexList.toIntArray(), id);
}
/** Returns an instance containing all the values of a given array larger or smaller of a given threshold.
* The vector will have size equal to the array length.
*
* @param value tha array of double.
* @param threshold the threshold.
* @param id the id of description associated with this vector.
* @return an immutable vector.
*/
public static ImmutableSparseVector getInstance (final double[] value, final double threshold, final int id) {
final IntArrayList indexList = new IntArrayList();
final DoubleArrayList valueList = new DoubleArrayList();
final int size = value.length;
// add value grater than threshold
for (int i = 0; i < size; i++) {
final double d = value[ i ];
if ( d < -threshold || d > threshold ) {
indexList.add (i);
valueList.add (d);
}
}
return new ImmutableSparseVector (size, valueList.toDoubleArray(), indexList.toIntArray(), id);
}
/** Returns an instance containing all the values of a given array larger than a given threshold.
* The vector will have the given size
*
* @param value tha array of double.
* @param threshold the threshold.
* @param id the id of description associated with this vector.
* @return an immutable vector.
*/
public static ImmutableSparseVector getInstance ( final int[] index, final double[] value, final int size, final double threshold, final int id) {
final IntArrayList indexList = new IntArrayList();
final DoubleArrayList valueList = new DoubleArrayList();
// add value grater than threshold
for (int i = 0; i < index.length; i++) {
if ( value[ i ] >= threshold )
{
indexList.add ( index [ i ] );
valueList.add ( value [ i ] );
}
}
return new ImmutableSparseVector (size, valueList.toDoubleArray(), indexList.toIntArray(), id);
}
public void set (final int idx, final double val) {
throw new UnsupportedOperationException ("ImmutableSparseVector is immutable");
}
public double get (final int idx) {
if (idx < 0 || idx >= size)
throw new IllegalArgumentException ("index out of range");
// shortcut
if ( idx > lastIndexValue && idx < lastIndexNextValue ) // beetwen indeces
return 0.0;
if ( idx == lastIndexNextValue ) { // next index
lastIndex++;
lastIndexValue = index[ lastIndex ];
lastIndexNextValue = lastIndex == nonZero - 1 ? size : index[ lastIndex + 1 ];
return value[ lastIndex ];
}
// shortcut failed...take the long way
int pos = Arrays.binarySearch( index, idx );
if ( pos < 0 ) { // value not found -> reset
lastIndexValue = lastIndexNextValue = -1;
return 0.0;
}
lastIndex = pos;
lastIndexValue = index[ lastIndex ];
lastIndexNextValue = lastIndex == nonZero - 1 ? size : index[ lastIndex + 1 ];
return value[pos];
}
public void add (final double alpha, final Vector v) {
throw new UnsupportedOperationException ("ImmutableSparseVector is immutable");
}
public void scale (final double alpha) {
throw new UnsupportedOperationException ("ImmutableSparseVector is immutable");
}
public void zero () {
throw new UnsupportedOperationException ("ImmutableSparseVector is immutable");
}
public double dotProduct (final Vector v) {
// check size
if (size != v.size)
throw new IllegalArgumentException ("vectors with different size");
// compute dot product
if (v instanceof ImmutableSparseVector) {
final ImmutableSparseVector sVector = (ImmutableSparseVector) v;
final double[] svValue = sVector.value;
final int[] svIndex = sVector.index;
final int last0 = nonZero, last1 = sVector.nonZero;
int i = 0, j = 0;
double dot = 0.0;
double c = 0.0, t, y;
while (i < last0 && j < last1) {
if (index[i] < svIndex[j])
i++;
else {
if (svIndex[j] < index[i])
j++;
else {
y = (value[i] * svValue[j]) - c;
t = dot + y;
c = (t - dot) - y;
dot = t;
//dot += value[i] * svValue[j];
i++;
j++;
}
}
}
return dot;
}
else if (v instanceof DenseVector) {
final double[] dvValue = ((DenseVector)v).value;
double dot = 0.0;
double c = 0.0, t, y;
for( int i = nonZero; i-- != 0; ) {
y = (dvValue[index[i]] * value[i]) - c;
t = dot + y;
c = (t - dot) - y;
dot = t;
//dot += dvValue[index[i]] * value[i];
}
return dot;
}
else
return super.dotProduct (v);
}
public double euclideanDistance (final Vector v) {
// check size
if (size != v.size)
throw new IllegalArgumentException ("vectors with different size");
// compute distance
if (v instanceof DenseVector)
return v.euclideanDistance(this);
else if (v instanceof ImmutableSparseVector)
return Math.sqrt (Math.abs (dotProduct (this) + v.dotProduct (v) - 2 * dotProduct (v)));
else
return super.euclideanDistance (v);
}
public double ell2Norm () {
if (ell2norm == INVALID_NORM) {
double tempNorm = 0.0;
int i = nonZero;
while (--i >= 0)
tempNorm += value[i] * value[i];
ell2norm = Math.sqrt (Math.abs (tempNorm));
}
return ell2norm;
}
public double ell1Norm() {
if ( ell1norm == INVALID_NORM ) {
double tempNorm = 0.0;
for(int i = nonZero; i-- != 0 ; )
tempNorm += Math.abs(value[i]);
ell1norm = tempNorm;
}
return ell1norm;
}
}
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