Sample.java

package org.drip.validation.evidence;

/*
 * -*- mode: java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 */

/*!
 * Copyright (C) 2020 Lakshmi Krishnamurthy
 * Copyright (C) 2019 Lakshmi Krishnamurthy
 * 
 *  This file is part of DROP, an open-source library targeting analytics/risk, transaction cost analytics,
 *  	asset liability management analytics, capital, exposure, and margin analytics, valuation adjustment
 *  	analytics, and portfolio construction analytics within and across fixed income, credit, commodity,
 *  	equity, FX, and structured products. It also includes auxiliary libraries for algorithm support,
 *  	numerical analysis, numerical optimization, spline builder, model validation, statistical learning,
 *  	and computational support.
 *  
 *  	https://lakshmidrip.github.io/DROP/
 *  
 *  DROP is composed of three modules:
 *  
 *  - DROP Product Core - https://lakshmidrip.github.io/DROP-Product-Core/
 *  - DROP Portfolio Core - https://lakshmidrip.github.io/DROP-Portfolio-Core/
 *  - DROP Computational Core - https://lakshmidrip.github.io/DROP-Computational-Core/
 * 
 * 	DROP Product Core implements libraries for the following:
 * 	- Fixed Income Analytics
 * 	- Loan Analytics
 * 	- Transaction Cost Analytics
 * 
 * 	DROP Portfolio Core implements libraries for the following:
 * 	- Asset Allocation Analytics
 *  - Asset Liability Management Analytics
 * 	- Capital Estimation Analytics
 * 	- Exposure Analytics
 * 	- Margin Analytics
 * 	- XVA Analytics
 * 
 * 	DROP Computational Core implements libraries for the following:
 * 	- Algorithm Support
 * 	- Computation Support
 * 	- Function Analysis
 *  - Model Validation
 * 	- Numerical Analysis
 * 	- Numerical Optimizer
 * 	- Spline Builder
 *  - Statistical Learning
 * 
 * 	Documentation for DROP is Spread Over:
 * 
 * 	- Main                     => https://lakshmidrip.github.io/DROP/
 * 	- Wiki                     => https://github.com/lakshmiDRIP/DROP/wiki
 * 	- GitHub                   => https://github.com/lakshmiDRIP/DROP
 * 	- Repo Layout Taxonomy     => https://github.com/lakshmiDRIP/DROP/blob/master/Taxonomy.md
 * 	- Javadoc                  => https://lakshmidrip.github.io/DROP/Javadoc/index.html
 * 	- Technical Specifications => https://github.com/lakshmiDRIP/DROP/tree/master/Docs/Internal
 * 	- Release Versions         => https://lakshmidrip.github.io/DROP/version.html
 * 	- Community Credits        => https://lakshmidrip.github.io/DROP/credits.html
 * 	- Issues Catalog           => https://github.com/lakshmiDRIP/DROP/issues
 * 	- JUnit                    => https://lakshmidrip.github.io/DROP/junit/index.html
 * 	- Jacoco                   => https://lakshmidrip.github.io/DROP/jacoco/index.html
 * 
 *  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.
 */

/**
 * <i>Sample</i> holds the Sample of Realizations.
 *
 *  <br><br>
 *  <ul>
 *  	<li>
 *  		Bhattacharya, B., and D. Habtzghi (2002): Median of the p-value under the Alternate Hypothesis
 *  			<i>American Statistician</i> <b>56 (3)</b> 202-206
 *  	</li>
 *  	<li>
 *  		Head, M. L., L. Holman, R, Lanfear, A. T. Kahn, and M. D. Jennions (2015): The Extent and
 *  			<i>Consequences of p-Hacking in Science PLoS Biology</i> <b>13 (3)</b> e1002106
 *  	</li>
 *  	<li>
 *  		Wasserstein, R. L., and N. A. Lazar (2016): The ASA’s Statement on p-values: Context, Process,
 *  			and Purpose <i>American Statistician</i> <b>70 (2)</b> 129-133
 *  	</li>
 *  	<li>
 *  		Wetzels, R., D. Matzke, M. D. Lee, J. N. Rouder, G, J, Iverson, and E. J. Wagenmakers (2011):
 *  			Statistical Evidence in Experimental Psychology: An Empirical Comparison using 855 t-Tests
 *  			<i>Perspectives in Psychological Science</i> <b>6 (3)</b> 291-298
 *  	</li>
 *  	<li>
 *  		Wikipedia (2019): p-value https://en.wikipedia.org/wiki/P-value
 *  	</li>
 *  </ul>
 *
 *  <br><br>
 *  <ul>
 *		<li><b>Module </b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/ComputationalCore.md">Computational Core Module</a></li>
 *		<li><b>Library</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/ModelValidationAnalyticsLibrary.md">Model Validation Analytics Library</a></li>
 *		<li><b>Project</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/src/main/java/org/drip/validation/README.md">Risk Factor and Hypothesis Validation, Evidence Processing, and Model Testing</a></li>
 *		<li><b>Package</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/src/main/java/org/drip/validation/evidence/README.md">Sample and Ensemble Evidence Processors</a></li>
 *  </ul>
 * <br><br>
 *
 * @author Lakshmi Krishnamurthy
 */

public class Sample implements org.drip.validation.evidence.NativePITGenerator
{
	private double[] _realizationArray = null;

	/**
	 * Sample Constructor
	 * 
	 * @param realizationArray The Sample Realization Array
	 * 
	 * @throws java.lang.Exception Thrown if the Inputs are Invalid
	 */

	public Sample (
		final double[] realizationArray)
		throws java.lang.Exception
	{
		if (null == (_realizationArray = realizationArray) ||
			0 == _realizationArray.length ||
			!org.drip.numerical.common.NumberUtil.IsValid (_realizationArray))
		{
			throw new java.lang.Exception ("Sample Constructor => Invalid Inputs");
		}
	}

	/**
	 * Retrieve the Realization Array
	 * 
	 * @return The Realization Array
	 */

	public double[] realizationArray()
	{
		return _realizationArray;
	}

	/**
	 * Apply the specified Test Statistic Evaluator to the Sample
	 * 
	 * @param testStatisticEvaluator The Test Statistic Evaluator
	 * 
	 * @return The Sample Test Statistic
	 * 
	 * @throws java.lang.Exception Thrown if the Inputs are Invalid
	 */

	public double applyTestStatistic (
		final org.drip.validation.evidence.TestStatisticEvaluator testStatisticEvaluator)
		throws java.lang.Exception
	{
		if (null == testStatisticEvaluator)
		{
			throw new java.lang.Exception ("Sample::applyTestStatistic => Invalid Inputs");
		}

		return testStatisticEvaluator.evaluate (_realizationArray);
	}

	@Override public org.drip.validation.hypothesis.ProbabilityIntegralTransform
		nativeProbabilityIntegralTransform()
	{
		org.drip.validation.evidence.TestStatisticAccumulator testStatisticAccumulator = new
			org.drip.validation.evidence.TestStatisticAccumulator();

		for (double realization : _realizationArray)
		{
			if (!testStatisticAccumulator.addTestStatistic (realization))
			{
				return null;
			}
		}

		return testStatisticAccumulator.probabilityIntegralTransform();
	}
}