no.uib.cipr.matrix.LowerSymmPackMatrix Maven / Gradle / Ivy
/*
* Copyright (C) 2003-2006 Bjørn-Ove Heimsund
*
* This file is part of MTJ.
*
* 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 2.1 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 library; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package no.uib.cipr.matrix;
/**
* Lower symmetric packed matrix. Same storage as
* {@link no.uib.cipr.matrix.LowerTriangPackMatrix LowerTriangPackMatrix}, but
* the upper triangular part is known by symmetry.
*/
public class LowerSymmPackMatrix extends AbstractSymmPackMatrix {
/**
* Constructor for LowerSymmPackMatrix
*
* @param n
* Size of the matrix. Since the matrix must be square, this
* equals both the number of rows and columns
*/
public LowerSymmPackMatrix(int n) {
super(n, UpLo.Lower);
}
/**
* Constructor for LowerSymmPackMatrix
*
* @param A
* Matrix to copy contents from. Only the entries of the relevant
* part are copied
*/
public LowerSymmPackMatrix(Matrix A) {
this(A, true);
}
/**
* Constructor for LowerSymmPackMatrix
*
* @param A
* Matrix to copy contents from. Only the entries of the relevant
* part are copied
* @param deep
* True if the copy is deep, else false (giving a shallow copy).
* For shallow copies, A must be a packed matrix
*/
public LowerSymmPackMatrix(Matrix A, boolean deep) {
super(A, deep, UpLo.Lower);
}
@Override
public void add(int row, int column, double value) {
if (column <= row)
data[getIndex(row, column)] += value;
}
@Override
public void set(int row, int column, double value) {
if (column <= row)
data[getIndex(row, column)] = value;
}
@Override
public double get(int row, int column) {
if (column <= row)
return data[getIndex(row, column)];
return data[getIndex(column, row)];
}
/**
* Checks the row and column indices, and returns the linear data index
*/
int getIndex(int row, int column) {
check(row, column);
return row + (2 * n - (column + 1)) * column / 2;
}
@Override
void copy(Matrix A) {
for (MatrixEntry e : A)
if (e.row() >= e.column())
set(e.row(), e.column(), e.get());
}
@Override
public LowerSymmPackMatrix copy() {
return new LowerSymmPackMatrix(this);
}
}