/*
* BufferIndexHelper.java
*
* Copyright (c) 2002-2016 Alexei Drummond, Andrew Rambaut and Marc Suchard
*
* This file is part of BEAST.
* See the NOTICE file distributed with this work for additional
* information regarding copyright ownership and licensing.
*
* BEAST 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
* of the License, or (at your option) any later version.
*
* BEAST 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 BEAST; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301 USA
*/
package dr.evomodel.treedatalikelihood;
import java.io.Serializable;
/**
* BufferIndexHelper - helper for double buffering of intermediate computation at nodes.
*
* @author Andrew Rambaut
* @author Marc Suchard
* @version $Id$
*/
public class BufferIndexHelper implements Serializable {
/**
* @param maxIndexValue the number of possible input values for the index
* @param minIndexValue the minimum index value to have the mirrored buffers
*/
public BufferIndexHelper(int maxIndexValue, int minIndexValue) {
this(maxIndexValue, minIndexValue, 0);
}
/**
* @param maxIndexValue the number of possible input values for the index
* @param minIndexValue the minimum index value to have the mirrored buffers
* @param bufferSetNumber provides a total offset of bufferSetNumber * bufferCount
*/
public BufferIndexHelper(int maxIndexValue, int minIndexValue, int bufferSetNumber) {
this.maxIndexValue = maxIndexValue;
this.minIndexValue = minIndexValue;
doubleBufferCount = maxIndexValue - minIndexValue;
indexOffsets = new int[doubleBufferCount];
storedIndexOffsets = new int[doubleBufferCount];
this.constantOffset = bufferSetNumber * getBufferCount();
}
public int getBufferCount() {
return 2 * doubleBufferCount + minIndexValue;
}
public void flipOffset(int i) {
assert(i >= minIndexValue) : "shouldn't be trying to flip the first 'static' indices";
indexOffsets[i - minIndexValue] = doubleBufferCount - indexOffsets[i - minIndexValue];
}
public int getOffsetIndex(int i) {
if (i < minIndexValue) {
return i + constantOffset;
}
return indexOffsets[i - minIndexValue] + i + constantOffset;
}
public void getIndices(int[] outIndices) {
for (int i = 0; i < maxIndexValue; i++) {
outIndices[i] = getOffsetIndex(i);
}
}
public void storeState() {
System.arraycopy(indexOffsets, 0, storedIndexOffsets, 0, indexOffsets.length);
}
public void restoreState() {
int[] tmp = storedIndexOffsets;
storedIndexOffsets = indexOffsets;
indexOffsets = tmp;
}
private final int maxIndexValue;
private final int minIndexValue;
private final int constantOffset;
private final int doubleBufferCount;
private int[] indexOffsets;
private int[] storedIndexOffsets;
}//END: class