Merge branch 'wvh_stochasticparameter'

Conflicts:
	Core/Core.pro

Core/Core.pro

@@ -24,7 +24,9 @@ SOURCES += \
     src/IRoughness.cpp \
     src/LayerInterface.cpp \
     src/IMaterial.cpp \
-    src/MaterialManager.cpp
+    src/MaterialManager.cpp \
+    src/StochasticGaussian.cpp \
+    src/MathFunctions.cpp \
 
 HEADERS += \
     inc/ISample.h \
@@ -44,7 +46,10 @@ HEADERS += \
     inc/OpticalFresnel.h \
     inc/IRoughness.h \
     inc/LayerInterface.h \
-    inc/MaterialManager.h
+    inc/MaterialManager.h \
+    inc/IStochasticParameter.h \
+    inc/StochasticGaussian.h \
+    inc/MathFunctions.h
 
 INCLUDEPATH += ./inc
 

Core/inc/IStochasticParameter.h

+#ifndef ISTOCHASTICPARAMETER_H
+#define ISTOCHASTICPARAMETER_H
+
+class IStochasticParameter
+{
+public:
+    virtual ~IStochasticParameter() {}
+    virtual void setToRandom()=0;
+    virtual void setToAverage()=0;
+};
+
+#endif // ISTOCHASTICPARAMETER_H

Core/inc/MathFunctions.h

+#ifndef MATHFUNCTIONS_H
+#define MATHFUNCTIONS_H
+
+#include <cstdlib>
+
+namespace MathFunctions
+{
+double Gaussian(double value, double average, double std_dev);
+
+double GenerateNormalRandom(double average, double std_dev);
+
+double StandardNormal(double value);
+
+double GenerateStandardNormalRandom();
+
+double GenerateUniformRandom();
+
+} // Namespace MathFunctions
+
+inline double MathFunctions::GenerateNormalRandom(double average, double std_dev)
+{
+    return GenerateStandardNormalRandom()*std_dev + average;
+}
+
+inline double MathFunctions::GenerateUniformRandom()
+{
+    int random_int = std::rand();
+    return (double)random_int / RAND_MAX;
+}
+
+#endif // MATHFUNCTIONS_H

Core/inc/StochasticGaussian.h

+#ifndef STOCHASTICGAUSSIAN_H
+#define STOCHASTICGAUSSIAN_H
+
+#include "IStochasticParameter.h"
+
+class StochasticDoubleGaussian : public IStochasticParameter
+{
+public:
+    StochasticDoubleGaussian(double average, double std_dev);
+    ~StochasticDoubleGaussian();
+
+    virtual void setToRandom();
+    virtual void setToAverage();
+
+    double getCurrent() { return m_current; }
+    double getRandom();
+    double getAverage();
+    double getStdDev() { return m_std_dev; }
+    double getCurrentProbDensity();
+
+private:
+    double m_current;
+    double m_average;
+    double m_std_dev;
+};
+
+
+#endif // STOCHASTICGAUSSIAN_H

Core/src/MathFunctions.cpp

+#include "MathFunctions.h"
+
+#include <cmath>
+
+double MathFunctions::Gaussian(double value, double average, double std_dev)
+{
+    return StandardNormal((value-average)/std_dev)/std_dev;
+}
+
+double MathFunctions::StandardNormal(double value)
+{
+    return std::exp(- value*value / 2.0) / std::sqrt(2.0*M_PI);
+}
+
+double MathFunctions::GenerateStandardNormalRandom()  // using Box-Muller transform
+{
+    double u1 = GenerateUniformRandom();
+    double u2 = GenerateUniformRandom();
+    return std::sqrt(-2.0*std::log(u1))*std::cos(2*M_PI*u2);
+}

Core/src/StochasticGaussian.cpp

+#include "StochasticGaussian.h"
+#include "MathFunctions.h"
+
+StochasticDoubleGaussian::StochasticDoubleGaussian(double average, double std_dev)
+    : m_average(average)
+    , m_std_dev(std_dev)
+{
+}
+
+StochasticDoubleGaussian::~StochasticDoubleGaussian()
+{
+}
+
+void StochasticDoubleGaussian::setToRandom()
+{
+    m_current = MathFunctions::GenerateNormalRandom(m_average, m_std_dev);
+}
+
+void StochasticDoubleGaussian::setToAverage()
+{
+    m_current = m_average;
+}
+
+double StochasticDoubleGaussian::getRandom()
+{
+    setToRandom();
+    return getCurrent();
+}
+
+double StochasticDoubleGaussian::getAverage()
+{
+    setToAverage();
+    return getCurrent();
+}
+
+double StochasticDoubleGaussian::getCurrentProbDensity()
+{
+    return MathFunctions::Gaussian(m_current, m_average, m_std_dev);
+}