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/*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: $RCSfile: itkNormalVariateGeneratorTest.cxx,v $
Language: C++
Date: $Date: 2005-02-08 03:18:41 $
Version: $Revision: 1.7 $
Copyright (c) Insight Software Consortium. All rights reserved.
See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notices for more information.
=========================================================================*/
#if defined(_MSC_VER)
#pragma warning ( disable : 4786 )
#endif
#include "itkNormalVariateGenerator.h"
#include "vnl/vnl_math.h"
int itkNormalVariateGeneratorTest(int, char* [] )
{
std::cout << "NormalVariateGenerator Test \n \n";
typedef float MeasureType;
typedef itk::Statistics::NormalVariateGenerator GeneratorType;
GeneratorType::Pointer generator = GeneratorType::New();
const int randomSeed = 14543 ; // any number to initialize the seed.
generator->Initialize( randomSeed );
const unsigned long numberOfSamples = 1000000UL;
double sum = 0.0f;
double sum2 = 0.0f;
std::cout << "Generating " << numberOfSamples << " samples... " << std::endl;
for(unsigned int i=0; i < numberOfSamples; i++)
{
const double variate = generator->GetVariate();
sum += variate;
sum2 += variate * variate;
}
const double mean = sum / numberOfSamples;
const double variance = sum2 / numberOfSamples - mean * mean;
std::cout << "Mean = " << mean << std::endl;
std::cout << "Variance = " << variance << std::endl;
// Test values for tolerance...
const double tolerance = 1e-2;
if( vnl_math_abs( mean - 0.0f ) > tolerance )
{
std::cout << "Mean is out of tolerance = " << tolerance << std::endl;
std::cout << "Test failed." << std::endl;
return EXIT_FAILURE;
}
if( vnl_math_abs( variance - 1.0f ) > tolerance )
{
std::cout << "Variance is out of tolerance = " << tolerance << std::endl;
std::cout << "Test failed." << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
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