/*
 * Encog(tm) Core v3.4 - Java Version
 * http://www.heatonresearch.com/encog/
 * https://github.com/encog/encog-java-core
 
 * Copyright 2008-2016 Heaton Research, 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.
 *   
 * For more information on Heaton Research copyrights, licenses 
 * and trademarks visit:
 * http://www.heatonresearch.com/copyright
 */
package org.encog.util.normalize.segregate.index;


/**
 * An index segregator is used to segregate the data according to its index.
 * Nothing about the data is actually compared. This makes the index range
 * segregator very useful for breaking the data into training and validation
 * sets. For example, you could very easily determine that 70% of the data is
 * for training, and 30% for validation.
 * 
 * This segregator takes a starting and ending index, as well as a smple size.
 * Everything that is between these two indexes will be used.  The sample 
 * repeats over and over.  For example, if you choose a sample size of 10, 
 * and a beginning index of 0 and an ending index of 5, you would get
 * half of the first 10 element, then half of the next ten, and so on.
 * 
 */
public class IndexSampleSegregator extends IndexSegregator {

	/**
	 * The starting index (within a sample).
	 */
	private int startingIndex;

	/**
	 * The ending index (within a sample).
	 */
	private int endingIndex;

	/**
	 * The sample size.
	 */
	private int sampleSize;

	/**
	 * The default constructor, for reflection.
	 */
	public IndexSampleSegregator() {
	}

	/**
	 * Construct an index sample segregator.
	 * @param startingIndex The starting index.
	 * @param endingIndex The ending index.
	 * @param sampleSize The sample size.
	 */
	public IndexSampleSegregator(final int startingIndex,
			final int endingIndex, final int sampleSize) {
		this.sampleSize = sampleSize;
		this.startingIndex = startingIndex;
		this.endingIndex = endingIndex;
	}

	/**
	 * @return The ending index.
	 */
	public int getEndingIndex() {
		return this.endingIndex;
	}

	/**
	 * @return The sample size.
	 */
	public int getSampleSize() {
		return this.sampleSize;
	}

	/**
	 * @return The starting index.
	 */
	public int getStartingIndex() {
		return this.startingIndex;
	}

	/**
	 * Should this row be included.
	 * @return True if this row should be included.
	 */
	public boolean shouldInclude() {
		final int sampleIndex = getCurrentIndex() % this.sampleSize;
		rollIndex();
		return ((sampleIndex >= this.startingIndex) 
				&& (sampleIndex <= this.endingIndex));
	}
}