NumericRange.java

/*
 * 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.mathutil;

import java.util.List;

import org.encog.util.Format;

/**
 * A numeric range has a high, low, mean, root-mean-square, standard deviation,
 * and the count of how many samples it contains.
 *
 */
public class NumericRange {
	/**
	 * Display to five decimal places.
	 */
	public static final int FIVE = 5;
	
	/**
	 * The high number in the range.
	 */
	private final double high;

	/**
	 * The low number in the range.
	 */
	private final double low;

	/**
	 * The mean value.
	 */
	private final double mean;

	/**
	 * The root mean square of the range.
	 */
	private final double rms;

	/**
	 * The standard deviation of the range.
	 */
	private final double standardDeviation;

	/**
	 * The number of values in this range.
	 */
	private final int samples;

	/**
	 * Create a numeric range from a list of values.
	 *
	 * @param values
	 *            The values to calculate for.
	 */
	public NumericRange(final List<Double> values) {

		double assignedHigh = 0;
		double assignedLow = 0;
		double total = 0;
		double rmsTotal = 0;

		// get the mean and other 1-pass values.

		for (final double d : values) {
			assignedHigh = Math.max(assignedHigh, d);
			assignedLow = Math.min(assignedLow, d);
			total += d;
			rmsTotal += d * d;
		}

		this.samples = values.size();
		this.high = assignedHigh;
		this.low = assignedLow;
		this.mean = total / this.samples;
		this.rms = Math.sqrt(rmsTotal / this.samples);

		// now get the standard deviation
		double devTotal = 0;

		for (final double d : values) {
			devTotal += Math.pow(d - this.mean, 2);
		}
		this.standardDeviation = Math.sqrt(devTotal / this.samples);
	}

	/**
	 * @return The high number in the range.
	 */
	public final double getHigh() {
		return this.high;
	}

	/**
	 * @return The low number in the range.
	 */
	public final double getLow() {
		return this.low;
	}

	/**
	 * @return The mean in the range.
	 */
	public final double getMean() {
		return this.mean;
	}

	/**
	 * @return The root mean square of the range.
	 */
	public final double getRms() {
		return this.rms;
	}

	/**
	 * @return The number of samples in the range.
	 */
	public final int getSamples() {
		return this.samples;
	}

	/**
	 * @return The standard deviation of the range.
	 */
	public final double getStandardDeviation() {
		return this.standardDeviation;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public final String toString() {
		final StringBuilder result = new StringBuilder();
		result.append("Range: ");
		result.append(Format.formatDouble(this.low, FIVE));
		result.append(" to ");
		result.append(Format.formatDouble(this.high, FIVE));
		result.append(",samples: ");
		result.append(Format.formatInteger(this.samples));
		result.append(",mean: ");
		result.append(Format.formatDouble(this.mean, FIVE));
		result.append(",rms: ");
		result.append(Format.formatDouble(this.rms, FIVE));
		result.append(",s.deviation: ");
		result.append(Format.formatDouble(this.standardDeviation, FIVE));

		return result.toString();
	}
}