/*
* Copyright (c) 2010, Lawrence Livermore National Security, LLC. Produced at
* the Lawrence Livermore National Laboratory. Written by Keith Stevens,
* kstevens@cs.ucla.edu OCEC-10-073 All rights reserved.
*
* This file is part of the C-Cat package and is covered under the terms and
* conditions therein.
*
* The S-Space package is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation and distributed hereunder to you.
*
* THIS SOFTWARE IS PROVIDED "AS IS" AND NO REPRESENTATIONS OR WARRANTIES,
* EXPRESS OR IMPLIED ARE MADE. BY WAY OF EXAMPLE, BUT NOT LIMITATION, WE MAKE
* NO REPRESENTATIONS OR WARRANTIES OF MERCHANT- ABILITY OR FITNESS FOR ANY
* PARTICULAR PURPOSE OR THAT THE USE OF THE LICENSED SOFTWARE OR DOCUMENTATION
* WILL NOT INFRINGE ANY THIRD PARTY PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER
* RIGHTS.
*
* 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 edu.ucla.sspace.matrix;
import edu.ucla.sspace.vector.DoubleVector;
import edu.ucla.sspace.vector.ScaledDoubleVector;
/**
* A decorator over {@link Matrix}s. Each row can be scaled by some
* scalar constant in O(1) time by applying the scalar value for each row during
* all gets and sets to values in the row.
*
* @author Keith Stevens
*/
public class RowScaledMatrix implements Matrix, java.io.Serializable {
private static final long serialVersionUID = 1L;
/**
* The backing instance of the matrix.
*/
private final Matrix m;
/**
* The {@link DoubleVector} for row scales.
*/
private final DoubleVector scales;
/**
* Creates a {@code RowScaledMatrix} that provides scaled read only access
* to the provided {@code Matrix} instance.
*/
public RowScaledMatrix(Matrix matrix, DoubleVector v) {
this.m = matrix;
this.scales = v;
}
/**
* {@inheritDoc}
*/
public int columns() {
return m.columns();
}
/**
* {@inheritDoc}
*/
public double get(int row, int col) {
return m.get(row, col) * scales.get(row);
}
/**
* {@inheritDoc}
*/
public double[] getColumn(int column) {
throw new UnsupportedOperationException("Cannot access column");
}
/**
* {@inheritDoc}
*/
public DoubleVector getColumnVector(int column) {
throw new UnsupportedOperationException("Cannot access column");
}
/**
* {@inheritDoc}
*/
public double[] getRow(int row) {
double[] values = m.getRow(row);
for (int i = 0; i < values.length; ++i)
values[i] *= scales.get(i);
return values;
}
/**
* {@inheritDoc}
*/
public DoubleVector getRowVector(int row) {
return new ScaledDoubleVector(m.getRowVector(row), scales.get(row));
}
/**
* {@inheritDoc}
*/
public int rows() {
return m.rows();
}
/**
* {@inheritDoc}
*/
public void set(int row, int col, double val) {
throw new UnsupportedOperationException("Cannot set values");
}
/**
* {@inheritDoc}
*/
public void setColumn(int column, double[] values) {
throw new UnsupportedOperationException("Cannot set values");
}
/**
* {@inheritDoc}
*/
public void setColumn(int column, DoubleVector values) {
throw new UnsupportedOperationException("Cannot set values");
}
/**
* {@inheritDoc}
*/
public void setRow(int row, double[] values) {
throw new UnsupportedOperationException("Cannot set values");
}
/**
* {@inheritDoc}
*/
public void setRow(int row, DoubleVector values) {
throw new UnsupportedOperationException("Cannot set values");
}
/**
* {@inheritDoc}
*/
public double[][] toDenseArray() {
return m.toDenseArray();
}
}