demo4_obj_fun.cxx File Reference

An example of a method to compute the objective function value of an image and then perform basic iterative gradient ascent. All parameters are parsed from a parameter file. More...

#include "stir/IO/OutputFileFormat.h"
#include "stir/recon_buildblock/PoissonLogLikelihoodWithLinearModelForMeanAndProjData.h"
#include "stir/IO/read_from_file.h"
#include "stir/is_null_ptr.h"
#include "stir/error.h"

Namespaces
	stir
	Namespace for the STIR library (and some/most of its applications)

Functions
int	main (int argc, char **argv)

Detailed Description

An example of a method to compute the objective function value of an image and then perform basic iterative gradient ascent. All parameters are parsed from a parameter file.

It illustrates

• basic class derivation principles
• how to use stir::ParsingObject to have automatic capabilities of parsing parameters files (and interactive questions to the user)
• how to initialise and setup a objective function object
• how to compute the objective function (log-likelihood) gradient
• how a basic iterative optimisation works (or may not, if parameters are altered)

Note that the same functionality could be provided without deriving a new class from stir::ParsingObject. One could have a stir::KeyParser object in main() and fill it in directly.

See README.txt in the directory where this file is located.

Author

Kris Thielemans and Robert Twyman