You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
90 lines
2.8 KiB
90 lines
2.8 KiB
//==============================================================================
|
|
//
|
|
// 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;
|
|
import simulator.sampler.Sampler;
|
|
|
|
/**
|
|
* SimulationMethod class for the APMC ("approximate probabilistic model checking")
|
|
* approach of Herault/Lassaigne/Magniette/Peyronnet (VMCAI'04).
|
|
* Case where 'approximation' is unknown parameter.
|
|
*/
|
|
public class APMCapproximation extends APMCMethod
|
|
{
|
|
public APMCapproximation(double confidence, int iterations)
|
|
{
|
|
this.confidence = confidence;
|
|
this.numSamples = iterations;
|
|
}
|
|
|
|
@Override
|
|
public void computeMissingParameterBeforeSim() throws PrismException
|
|
{
|
|
approximation = Math.sqrt((0.5 * Math.log(2.0 / confidence)) / numSamples);
|
|
missingParameterComputed = true;
|
|
}
|
|
|
|
@Override
|
|
public Object getMissingParameter() throws PrismException
|
|
{
|
|
if (!missingParameterComputed)
|
|
computeMissingParameterBeforeSim();
|
|
return approximation;
|
|
}
|
|
|
|
@Override
|
|
public String getParametersString()
|
|
{
|
|
if (!missingParameterComputed)
|
|
return "approximation=" + "unknown" + ", confidence=" + confidence + ", number of samples=" + numSamples;
|
|
else
|
|
return "approximation=" + approximation + ", confidence=" + confidence + ", number of samples=" + numSamples;
|
|
}
|
|
|
|
@Override
|
|
public Object getResult(Sampler sampler) throws PrismException
|
|
{
|
|
// We may use 'approximation' to compute the result, so compute if necessary
|
|
// (this should never happen)
|
|
if (!missingParameterComputed)
|
|
computeMissingParameterBeforeSim();
|
|
return super.getResult(sampler);
|
|
}
|
|
|
|
@Override
|
|
public SimulationMethod clone()
|
|
{
|
|
APMCapproximation m = new APMCapproximation(confidence, numSamples);
|
|
m.approximation = approximation;
|
|
m.missingParameterComputed = missingParameterComputed;
|
|
m.prOp = prOp;
|
|
m.theta = theta;
|
|
return m;
|
|
}
|
|
}
|