code: //==============================================================================
  //	
  //	Copyright (c) 2002-
  //	Authors:
  //	* Vincent Nimal <vincent.nimal@comlab.ox.ac.uk> (University of Oxford)
  //	* Dave Parker <david.parker@comlab.ox.ac.uk> (University of Oxford)
  //	
  //------------------------------------------------------------------------------
  //	
  //	This file is part of PRISM.
  //	
  //	PRISM is free software; you can redistribute it and/or modify
  //	it under the terms of the GNU General Public License as published by
  //	the Free Software Foundation; either version 2 of the License, or
  //	(at your option) any later version.
  //	
  //	PRISM 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 General Public License for more details.
  //	
  //	You should have received a copy of the GNU General Public License
  //	along with PRISM; if not, write to the Free Software Foundation,
  //	Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  //	
  //==============================================================================
  
  package simulator.method;
  
  import prism.PrismException;
  
  /**
   * SimulationMethod class for the APMC ("approximate probabilistic model checking")
   * approach of Herault/Lassaigne/Magniette/Peyronnet (VMCAI'04).
   * Case where 'confidence' is unknown parameter.
   */
  public class APMCconfidence extends APMCMethod
  {
  	public APMCconfidence(double approximation, int iterations)
  	{
  		this.approximation = approximation;
  		this.numSamples = iterations;
  	}
  
  	@Override
  	public void computeMissingParameterBeforeSim() throws PrismException
  	{
  		if (approximation * approximation * numSamples < Math.log(2.0) / 2.0) {
  			String msg = "For APMC, samples (N) and approximation (eps) must satisfy N*eps^2 >= ln(2)/2";
  			msg += ". Increase samples and/or approximation";
  			throw new PrismException(msg);
  		}
  		confidence = 2.0 / Math.exp((numSamples * approximation * approximation) * 2.0);
  		missingParameterComputed = true;
  	}
  
  	@Override
  	public Object getMissingParameter() throws PrismException
  	{
  		if (!missingParameterComputed)
  			computeMissingParameterBeforeSim();
  		return confidence;
  	}
  
  	@Override
  	public String getParametersString()
  	{
  		if (!missingParameterComputed)
  			return "approximation=" + approximation + ", confidence=" + "unknown" + ", number of samples=" + numSamples;
  		else
  			return "approximation=" + approximation + ", confidence=" + confidence + ", number of samples=" + numSamples;
  	}
  	
  	@Override
  	public SimulationMethod clone()
  	{
  		APMCconfidence m = new APMCconfidence(approximation, numSamples);
  		m.confidence = confidence;
  		m.missingParameterComputed = missingParameterComputed;
  		m.prOp = prOp;
  		m.theta = theta;
  		return m;
  	}
  }
  