/*******************************************************************************
* Copyright 2014 Analog Devices, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
********************************************************************************/
package com.analog.lyric.dimple.factorfunctions.core;
import java.util.Objects;
import net.jcip.annotations.NotThreadSafe;
import com.analog.lyric.dimple.model.domains.JointDomainIndexer;
@NotThreadSafe
final class SparseFactorTableIterator extends FactorTableIteratorBase
{
/*-------
* State
*/
private final SparseFactorTable _table;
/*--------------
* Construction
*/
SparseFactorTableIterator(SparseFactorTable table)
{
_table = table;
_sparseIndex = -1;
}
/*-------------------
* Iterator methods
*/
@Override
public boolean hasNext()
{
int[] indices = _jointIndices;
int si = _sparseIndex;
double w = _weight, e = _energy;
boolean result = advance();
_jointIndices = indices;
_sparseIndex = si;
_weight = w;
_energy = e;
return result;
}
/*------------------------------
* IFactorTableIterator methods
*/
@Override
public boolean advance()
{
if (done())
{
return false;
}
_entry = null;
return sparseAdvance();
}
@Override
public JointDomainIndexer domains()
{
return _table.getDomainIndexer();
}
@Override
public int[] indicesUnsafe()
{
return Objects.requireNonNull(_jointIndices);
}
@Override
public int jointIndex()
{
return -1;
}
@Override public boolean skipsZeroWeights()
{
return true;
}
/*-------------------------
* FactorTableIteratorBase
*/
@Override
boolean done()
{
return _sparseIndex >= _table.sparseSize();
}
@Override
void makeEntry()
{
if (!done())
{
_entry = new FactorTableEntry(_table.getDomainIndexer(), _sparseIndex, _jointIndices, _energy, _weight);
}
}
/*---------
* Private
*/
private boolean sparseAdvance()
{
for (int si = _sparseIndex + 1, end = _table.sparseSize(); si < end; ++si)
{
final double weight = _table.getWeightForSparseIndex(si);
if (weight != 0.0)
{
_sparseIndex = si;
_jointIndices = _table.sparseIndexToIndicesUnsafe(si);
_weight = weight;
_energy = _table.getEnergyForSparseIndex(si);
return true;
}
}
_weight = 0.0;
_energy = Double.POSITIVE_INFINITY;
return false;
}
}