ossimGDoptimizer Class Reference

Simple Gradient Descent optimizer for ossim. More...

#include <ossimGDoptimizer.h>

Public Member Functions
	ossimGDoptimizer ()
	Public Copy constructor. More...
	ossimGDoptimizer (const ossimGDoptimizer &src)
	Public Copy constructor. More...
	~ossimGDoptimizer ()
	Destroys the object !DOES NOT DELETE FUNCTION! More...
	ossimGDoptimizer (ossimTerm *function)
	Public Constructor with a preset function. More...
bool	setFunction (ossimTerm *function)
	Sets the function to be optimized. More...
std::vector< ossim_float64 >	optimize (std::vector< ossim_float64 > startPoint, ossim_float64 gamma=0.001, ossim_float64 precision=0.0001, ossim_uint32 maxEpoch=10000) const
	Optimizes the function. More...

Private Attributes
ossimTerm *	m_func

Detailed Description

Simple Gradient Descent optimizer for ossim.

Author

Dylan Thomas Cannisi

Date

07/24/2017

   See top level LICENSE.txt file.

Definition at line 19 of file ossimGDoptimizer.h.

Constructor & Destructor Documentation

ossimGDoptimizer() [1/3]

ossimGDoptimizer::ossimGDoptimizer

(

)

Public Copy constructor.

Simple Gradient Descent optimizer for ossim.

Author

Dylan Thomas Cannisi

Date

07/24/2017

See top level LICENSE.txt file.

Public Copy constructor

Definition at line 17 of file ossimGDoptimizer.cpp.

References m_func.

                                  {
    m_func = nullptr;
}

ossimGDoptimizer() [2/3]

ossimGDoptimizer::ossimGDoptimizer

(

const ossimGDoptimizer &

src

)

Public Copy constructor.

Parameters

[in]

src

The object to be copied (copies pointer not a copy of function)

Definition at line 27 of file ossimGDoptimizer.cpp.

References m_func.

                                                             {
    m_func = src.m_func;
}

~ossimGDoptimizer()

ossimGDoptimizer::~ossimGDoptimizer

(

)

Destroys the object !DOES NOT DELETE FUNCTION!

Definition at line 35 of file ossimGDoptimizer.cpp.

                                   {
}

ossimGDoptimizer() [3/3]

ossimGDoptimizer::ossimGDoptimizer

(

ossimTerm *

function

)

Public Constructor with a preset function.

Parameters

function

The function to be optimized

Definition at line 44 of file ossimGDoptimizer.cpp.

References m_func.

                                                     {
    m_func = function;
}

Member Function Documentation

optimize()

std::vector< ossim_float64 > ossimGDoptimizer::optimize	(	std::vector< ossim_float64 >	point,
		ossim_float64	gamma = 0.001,
		ossim_float64	precision = 0.0001,
		ossim_uint32	maxEpoch = 10000
	)		const

Optimizes the function.

Parameters

[in]	startPoint	The start point at which the algorithm starts its descent
[in]	gamma	Determins the step size as a function of the gradient
[in]	precision	The stopping point at which the algorithm will no longer descend
[in]	maxEpoch	The stopping point to limit infinite loops.

Returns

the optimial minima

Definition at line 76 of file ossimGDoptimizer.cpp.

References ossimTerm::derivative(), and m_func.

                                                                                                                                                             {

    ossim_uint32 iter = 0;
    ossim_float64 step = 10000;

    std::vector<ossimTerm*> derivative;
    for(size_t i = 0; i < point.size(); ++i){
        derivative.push_back(m_func->derivative(i));
    }

    std::vector<ossim_float64> prevPoint;
    while(step > precision && iter < maxEpoch){
        step = 0;
        prevPoint = point;
        for(size_t i = 0; i < point.size(); ++i){
            point[i] += -gamma * derivative[i]->evaluate(point);
            step += pow(point[i]-prevPoint[i], 2);
        }
        step = sqrt(step);
    }

    for(size_t i = 0; i < derivative.size(); ++i){
        delete derivative[i];
    }

return point;
}

setFunction()

bool ossimGDoptimizer::setFunction

(

ossimTerm *

function

)

Sets the function to be optimized.

Parameters

function

The function to be optimized

Returns

whether or not the optimizer already contained a function

Definition at line 56 of file ossimGDoptimizer.cpp.

References m_func.

                                                     {
    bool retVal = false;

    if(m_func != nullptr) retVal = true;
    m_func = function;

return retVal;
}

Member Data Documentation

m_func

ossimTerm* ossimGDoptimizer::m_func

private

Definition at line 68 of file ossimGDoptimizer.h.

Referenced by optimize(), ossimGDoptimizer(), and setFunction().

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The documentation for this class was generated from the following files:

• ossimGDoptimizer.h
• ossimGDoptimizer.cpp